Need help...next addition to my system

One of the best aspects of this musical hobby we all love is upgrading or adding to an existing system, making tweaks to what we already like and enjoy. I'm primarily an analog guy but will use streaming for longer/background listening and for checking out new albums prior to purchasing it on vinyl. I'm at the point of making an addition and would love to get feedback on the most logical next step. My room is small/medium sized (240 ft2). I'm currently working with:

- Dynaudio Heritage Special 2-way speakers

- Octave V80SE integrated with KT150 tubes with added Super Black Box and internal MC phono stage (very decent phono stage)

- Rega P10 with pre-mounted Apheta 3 cartridge

- Niagara 5000 and all Audioquest cables throughout (high-end mythical creatures power and speaker cabling)

My thoughts with respect to additions, likely in this order: 

1. Sub: REL Carbon Special OR JL Audio Fathom f112 (single one for now)

2. Separate phono stage: ModWright PH9.0x, PS Audio Stellar, Parasound JC3+ 

3. Cartridge: Hana Umami Red, ZYX Ultimate Airy X, Etsuro Cobalt Blue

4. DAC/streamer: Lumin T2

Please also recommend other pieces/products I should audition in these categories you think may mate well with existing pieces. Thanks for any suggestions!

Happy New Year as well to everyone!