Docker as mentioned above is great especially if you’re going down the homelab rabbit hole. You’ll find it really useful to get familiar with for future projects.

Another alternative is to install DietPi. It’s an operating system for a raspberry pi. It has all these programs you mentioned with install scripts including docker and installing (and updating) is as easy as checking a box. Also has a pretty good community in case you run into an edge case.

eBay is your friend, Shield came out about 9 years ago so lots on the used market. Also the phoning home for the paranoid can also be handled. Since it’s been around for so long there’s not a lot left someone hasn’t already figured out. Maybe not the perfect answer but worth considering. As a media player it just works and it’s tried and true.

Have you looked into maybe getting a shield and changing out the launcher? It’s a great emulator and will play any video file thrown at it. Worth looking into if you can’t find any sbc alternative.