It really kinda depends on what type of Minecraft server you’re running. I was running Plex and Minecraft on unRaid with like 16gigs of ram and an i3 8100 and it was fine until I started doing more intense moded Minecraft. The iGPU in Intel processors can handle transcoding really well so it’s a pretty good all in one solution. I imagine if you’re going to heavily modded Minecraft you could probably get away with a current gen i5 or maybe even i3 if you’re on a budget. Looks like the i3 13100 has hyper threading and my old 8100 didn’t. Not sure how big of a difference it would make.
I’ll keep using it until they no longer let me, I guess. Pretty sure OMV and TrueNAS have matured enough to fall to if unRAID decides to go full subscription, at least.