Server Recommendations

Hey all, I need some advice from people smarter than me. I currently have truenas running on a little mini pc, running an arr stack and some smart home things, and it's working really good. I am going to upgrade to a full size rack mount server though, because I want to start playing with LLMs, and consolidate my mini pc and NAS into one machine. I have a super micro CSE-826 case, and 3x 24tb seagate hard drives, and will slowly be getting more. I’m looking for recommendations on a good motherboard/cpu combo to use. I have an Nvidia t400 gpu that I will use for now until I find a good deal on an upgrade.

crossposted to a few different subs