You shortlisted zen streamer and allo digione signature. I haven't used zen streamer or the allo digione signature. But have used other allo devices (allo usbridge signature, allo revoliution dac, allo piano dac, allo volt plus amp). The usbridge signature has a provision to attach the digione hat. But the underlying hardware is the RPI compute model. So if you use the RPI 4b, it is more than enough. Aso since you are using RPI, you can do almost anything because the underlying OS is linux. You can install any software be it spotify, mpd, airplay, logitech media server, etc. Zen streamer will restrict you to its own software/firmware. Also you are free to attach any dac tomorrow on the IO header port. You will be future proofed.
With my RPI4 based setup I'm able to
1. Play music in any room
2. Play spotify, airplay
3. Stream music to any TV in the house using LMS and chromecast plugin with the artwork.
4. Act as file server (SAMBA share) for all my mobile clients to play my music.
5. Control the music playback from any device (macbook, linux laptop, android phones, IOS devices ipod touch, ipad).
6. Can connect any USB dac to the RPI
7. Can also stream losless music of my local music files on http or https by configure /etc/mpd.conf
8. Control music using IR remote
...