I was considering going down that road with audio but my RPI is primarily used for transmitting weather data from my weather station (weewx) and home automation (Home Assistant Supervised). I also use my RPI headless and it is an RPI 4b 8Gig running on a 1TB SSD. So, I was going to go down that same road as it still has I believe alot more capacity to handle more “work” and I do have a huge library of music - and right now I have no sound coming from it at all - BUT…
I understand that even the RPI 4 has a pretty lousy audio support and most people that are seriously trying to get something really decent out of it for audio purposes - have typically used a USB connection to the RPI for not a speaker - but specialized audio add-ons to beef up the hardware to supporting better codecs and the like (getting near the edge of my knowledge here). So, if you are a serious audiophile, I would strongly encourage you to look into “sound card raspberry pi” under google google or duckduckgo. A quick search I found was: https://www.hifiberry.com/
Hope that helps!