I did a 4 node Pi4 kubernetes cluster for about 5 years. The learning experience was priceless. I think most notable was learning to do proper multiarch container builds to support arm and x86_64. That being said, about half a year ago I decided to try condensing it all into two n100 nuc-like clones and keep one pi as the controller. For me and my apps and use cases there was no going back. Performance gains were substantial and in this regard I think I was hobbling myself after the educational aspect plateaued.

You might check out wiim stuff. They seem to be the darling of budget streaming for the moment.

I’ve had a good experience so far with two minipcs, mele quieter 4c for kodi, and a morefine m9 (I think this one is branded as mipowcat in the EU). They’re both n100, the m9 can go up to 32gb of ram although it is picky about what modules it will accept. I use the m9 for jellyfin and about 10 other services. Quick sync works great as far as I’ve tested it. For jellyfin I’m relying mostly on direct streaming, but I tried a few episodes with forcing some transcoding by using Firefox for playback and it worked fine.