Suggestions for a streamer only (I have a great DAC)

Lots of other options but software is a partial driver of your choice.  The interface you want to use matters and then picking the device with that interface is best approach.  I use Roon so I am almost universally focused on a server/player solution.  I think this sounds best and find having a server as a buffer vs a very volatile internet will outperform the best standalone streamers that I have heard.  

Do you have a server?  What service do you want to stream?  Have you used any software that you liked?

If you are looking for a Roon or UPnP end-point, the Bricasti M5 is very good.  The best output is AES and it is a unit that sells extremely well for Bricasti.  This is not a standalone streamer.  You aren't going to play Tidal or Qobuzon it without software that talks to the device on your network.  

Another alternative that is a bit more feature rich is the Chord 2Go/2Yu.  I have been using one of these to connect to a lot of DACs.  The USB and Coax outputs are excellent.  The biggest challenge I have is getting my head around this little 4" x 4" x1" unit is doing all it does.  It does have wireless built in but sounds better wired.

Lumin makes a U1 and U1 Mini.  I hear these are nice units that are quite stable.  This is a standalone "streamer" and does not require a server.  Lumin has their own software.

Both Auralic and Aurender I am sure also make devices that will meet your needs.  I do not know the exact models.  

IMO, the best solution would be to get something like a Bricasti M5 and pair it with a Roon Nucleus.  This would be under your budget even with a lifetime subscription to Roon and will deliver best performance for local files, Tidal and Qobuz.

For your budget and best sound I would get a Roon Nucleus and a Bricasti M5. The Roon Nucleus is a computer that runs one piece of software. Roon Core. Nothing else. It has a power button and a couple setting that anyone can walk you through when you setup the unit. This needs to be on your network, near your router.

The M5 needs an Ethernet connection. It does not need to be near the Nucleus and takes care of the player part of the process.  It gets your files ready to go to the DAC.

This will sound amazing. Be on budget. And can be purchased from a few retailers with 30 day return policies.

@antigrunge2 I have not spent much time with any Innuos products and have not heard their server playing their software. Last I heard one was a statement running Roon. The only thing I know about their software is that it is supposed to sound great but was a bit unstable on release. I assume Innuos worked diligently to correct those issue as it is a big point of differentiation for them.

I have spent a lot of time with a Nucleus and Bricasti items. I agree that a Nucleus as a player and renderer is mediocre. It is also relatively modestly priced.  Strictly used as a server sending a signal to a separate player, it is far superior to using it as a single source connected via USB. I cannot answer if Nucleus/Bricasti combo is as good as Innuos as I have not tested it but Nucleus/Bricasti is much better than Nucleus alone. Nucleus alone is MUCH better than dedicated PC/Laptop/Mac Mini.

No one claims that Roon is best sounding software. Pretty universally Roon core with Squeeze as a front end is deemed one of the best sounding options. HQ Player is very, very good. I have heard the Innuos software is supposed to be better and Pink Faun’s native software is arguably the best of them all. There is a big difference between not being best sounding and sounding bad. IMO, Roon sound is very good and when one considers the UI, it is not shocking why it is so popular.

The OP is looking for a simple solution that will sound good and is easy to control from a tablet. I stand by my recommendation against those parameters. Innuos may be an excellent alternative.