If you’re willing to pay ~$300 you can grab an Amazon renewed Dell Poweredge with like 192gb ram, 8TB RAID HDDs, 2 Xeons, etc. Pretty good deal IMO.

that will definitely work well

I’ve been using a 2009 laptop which works alright for my needs but that looks cool

I have the same CPU for my server that's very similar to that PC, I have like 10 (kind of lightweight) containers running and it gets around 10-15% usage, I think it gets up to around 30-50% while running a Paper MC server with a few people on. The RAM may be limiting, I have 40GB and I'm using around 30GB. You should get a second drive that is the same capacity to have redundancy in-case of drive failure (write speeds are limited to the slowest drive in a RAID1 though). You may also want to get another drive for booting off of (even a USB drive is fine for Linux or a hypervisor like Proxmox).Btw, I recommend Proxmox, it's a very good hypervisor for a home server. For price, it seems alright, I got mine for a lot cheaper but it was on clearance and only came with 8GB of RAM and a 500GB hard drive.

As long as you invite me to the minecraft server, I think it’s a great idea. (do not take this as financial advice, I just like playing minecraft)

at a quick glance, it seems pretty good, but I can see the RAM being the biggest limiting bottleneck if running a server (if you just have like 10 people on though, it won't be too bad if you just limit Java memory)