How would you upgrade my entry level system?

Another + for room treatment.
The room and setup will give you AT LEAST 50% of what you will (or won't) hear. 
No gear change is as effective as meticulous setup and treatment.

Thanks for all the responses.

Ive made 2 changes so far.

Signed up for Tidal $20 per month (post trial).  Really enjoying access to lots of new and old music at decent quality.

Primarily playing tidal via Oppo 105 to take advantage of the dac vs Sonos Connect.

it sounds much better than before.

what do I do next ? Not sure. I could do with new power cables for sure as using standard ones. 

I'm reluctant to change the new Audiovector Q3 floorstanders.

Potentially they lack some bass but may hold in case we move house.

Was considering changing the brio r, would Naim Uniti be an upgrade and convenient ? I heard they are good fit with Audiovector.  Or a Hegel model.  

Not sure what I'll do next but glad I have some ideas and that the above has led to some enhancements already. 

It would be interesting to hear what decision you made and how you feel about it now.

If you’re still weighing up your options I’d say spend the whole amount on new loudspeakers, full bandwidth designs flat down to at least 40Hz if you have the bookshelf QRs. If you have the QR5 floorstanders then your question becomes a lot more difficult as then your system looks pretty good already. You won’t need to ever change your amp until you have speakers that can benefit from more than the 50 watts per channel the Brio R can deliver.

In any the easy answer for me is to suggest spending your money on whatever makes you want to listen to music more.

Remember, the most expensive system in the world is just another example of money gone up in smoke if you hardly ever feel like listening to it.

Keep the Brio R, then use the $5k as follows: $2k on new on Teac nt505 dac/streamer (best streamer under $5k imo) and $3k on new or used speakers.

Speakers are such a personal choice. I’d look at Focal Aria 936, Spendor A4, Dynaudio Excite X? whichever model hits that price point.

Then subscribe to $20/mo Tidal or Amazon hifi or Qobuz. Good luck!!

note the Teac requires Ethernet connection (not WiFi). If you can’t do Ethernet at install location then disregard my recommendation 

Think of it like you're building a house. First, start with a solid foundation ie. room treatments (GIK or ASC) and vibration control (Herbies has affordable options). Next. address your incoming power ie. power cords (many options out there, buy used) and outlets ( also dedicated lines of possible). Doing these things will pay off in the long run no matter what gear you get in the future. Good listening. Jeff

Don't know what you're using but you might consider upgrading your power cables. 

As someone else stated, for $5k I would just start over and sell your current equipment.  But, for an upgrade path and more conservative approach...

Since you already listen to ripped CDs (hopefully at full resolution), why upgrade the CD player? Save the money for other components. I would do the following:
(1) replace the Connect with a Bluesound Node 2i.  Good server and decent DAC (and you can always add an external DAC later). $500
(2) Get an entry level power condition from Furman or Audioquest.  $200 or so.This actually made a noticeable improvement in my modest, second system.
(3) Get a high-res subscription service like Tidal or Qoboz.

I would do this before anything amp or speaker related.  See how they sound with an improved front end before moving from there. 

I like the existing sound.
would just like to more captivated, can't articulate it any better than that.

Don't need to. Captivated is perfect. Captivated happens when your senses detect something is really there. Captivated is better than fascinated. Captivated you are caught. You are drawn in. You can't, or even better don't want to, get away.

What gets you to captivated isn't in-your-face dynamics or flat frequency response or any of the normal audiophile BS. What gets you captivated is the sense of subtle inner detail lurking just beneath the surface. Kind of thing makes you want to listen closer and more intently. Deeper and deeper into the recording.

You can buy the best speakers, amps and CD players in the world and you cannot get to captivated that way. No way. Never in a million years. All you will hear doing that is your crap lamp cord, patch cords, and freebie power cords. And boy will you hear them good and boy will it be annoying.

The way to captivating is carefully auditioning at home every one of your components including all the wires until you find the ones that beautifully balance and bring out the best in all the other components. Captivating doesn't have to cost a lot of money. It costs time. And effort. But man is it worth it. 

... and I'm assuming you have fully broken in your equipment - that means 300+ hours of continuous play (I usually do double that): most never really break their equipment in, consequently never really knowing how good their equipment really is...

... FIRST MAKE YOUR OWN SPEAKER CABLES: twist lengths of 14g Solid Core Copper wire from an electrical supply place (I paid $0.20/lf), install with bare wires and play for 300 hours. You may find you have rebirthed your system with enough improvement that you'll buy more music and have an increase in enjoyment instead of more neurosis...

I would look for some gently used equipment. Maggie 1.7i speakers about $1400, Parasound Halo integrated $1600 a good sub $700 and you'll have some great equipment and sound to match with money left over.

My thoughts:

1) System setup. Have you spent time dialing in the speaker and listening position?
2) Room Treatments- Without knowing anything about your room it is hard to suggest, but often they can make an tremendous difference. With GIK you can get their Room Kits starting at under $600, and if you send photos and measurements of your room, GIK will suggest placement (they do a lot of professional audio installations and know their stuff).  
3) Absolutely upgrade your streaming service. You can get CD quality from Deezer, Tidal, or Qobuz. Tidal offers some higher resolution streaming, but is more focused on MQA now (you can research MQA yourself, the short is it is a highly debated area of audio) and Qobuz offers hi resolution streaming.
4) With the Sonos, you can get pretty good sound out of it if you use an outboard DAC, but it is limited to 48khz, so no high res streaming. If you keep keep the Sonos, I would try a Schiit Modi Multibit or Bifrost DAC. That said, moving up to something like a Bluesound streamer with an outboard DAC is worth doing.

And quit streaming, if you want to be captivated...

Get a pair of Tekton DI's for $3K and sell or put those Audiovectors in another room! Changing speakers will make the most difference (and improvement) over anything else! Honest!

Thanks for the responses.
Guess I have some thinking to do.
short term: try Tidal streaming. Consider non Sonus option. 
Medium term: consider upgrade on speakers and then build new system.
I like the existing sound.
would just like to more captivated, can't articulate it any better than that.

Five grand in the context of your current system is a lot more than an upgrade and in my book calls for some serious thought.

Sounds like right now you are mostly using it for playing background music. With maybe some occasionally more dedicated listening. The point of this isn’t to see how good I am at guessing games. Its to get you thinking.

Which matters more, how great it sounds sitting in one precisely defined sweet spot? Or anywhere around the room? How likely is this to change over time? Ditto the room- will you be staying put or moving?

What are your more longer term goals? You could plow the whole five grand into a classic highly regarded speaker, one so good you could spend the next however many years building an awesome system around them and still love them. Or you might be a whole lot happier to budget the whole five grand to a whole new system.

This kind of thinking it through approach is the only way I know of getting anywhere but broke. Anything else boils down to asking a bunch of random people how they would upgrade a bunch of stuff they never would have bought in the first place. Which you just did. And got a good answer anyway.

BTW, I always recommend GIK for being pretty, effective and inexpensive.

You can do some great room treatments for free or cheap.  Spotify and Pandora have very poor sound quality. Some love the 105 for CD and some not at all. Sonos Connect also has poor DAC and a high jitter signal from digital out. 

Room treatment.