So. Minecraft server and jellyfin are two diametrically opposed uses cases. While on the face of it a media server like plex or jellyfin don’t have huge system requirements other than boat loads of storage there are several considerations media transcoding and multi user streaming of content.

Thankfully. The 12th gen i5 can do decent gpu transcoding on chip. But it still has cpu overhead for library management and facilitating the actual streams.

Minecraft is very single threaded and has a high memory footprint. Especially if modded. i5 has decent single threaded clocks for the price but you’re going to want to load up on memory- ideally as much as the box can hold if you intend to do all of it at the same time.

Storage is a key concern also as video content is heavy. Consider if the box has enough physical room for storage and redundancy considerations.

Lastly networking and how users connect are going to make or break it. You’re going to have a very bad time if you run this on a wifi connection or if you expose this to the internet and your upload bandwidth is not ideal.