Lots of choices for sure. I haven’t built a PC in years but I’d start with looking at the requirements for the Minecraft & Jellyfin server, maybe shoot a bit higher to future-proof the build, then browse PC part picker builds to find combos that have worked well for others?
Best of luck to you.
I’ve been happy with Graphene on my Pixel 7. Only con is Google Wallet doesn’t work, but not a big deal for me personally. I also like that I can deny apps network access: I’ve been using Gboard without network access, which makes me feel a bit better in regards to privacy.