This sounds like a job for a raspberry pi 5 with an m.2 hat for storage, software is a less important choice here, so ubuntu's raspberry pi flavour would be my choice. Just make sure you give it power in a form it likes.
It's bizarre how blatent this is. Google has so much power over web standards that Mozilla have to work really hard to make firefox work, but YouTube don't bother being subtle or clever and just write 'if Firefox, get stuffed' in plain text for everyone to see.