The Le Potato AML-S905X-CC has h.264 and h.265 decoders up to 4k, emmc connector So you don’t have to run off an SD card. I’ve used it as a media player and its pretty damn solid. I can’t speak to streaming games because I don’t do that, so I don’t know if it’s a different format. It does not have a powerful processor, so if the stream is encoded differently I wouldn’t expect it to be very good.
Its pretty old, around rpi3 performance, but having the decoders in there make it better than the RPI 4 for playing those types of videos.
Rpis are great for always on things with low power use but not if you have many low power use things. But you would really be feeling that 1GB of ram, and microSDs kind of suck to run off of. I would honestly save the $25 and put it toward one of the $100 tiny/mini/micros.
I would not steer you away from an RPI if you don’t have one, they are very useful and fun, but if you’re looking for learning about self hosting, you’re probably going to end up getting something more powerful anyway