homelab

I would recommend looking at 2016-era Xeon E5 processor and appropriate motherboard with plenty of memory. Some of these Xeons had up to 22 cores. I got Xeon E5-2690 with 14 cores and 28 threads for a whopping 50.00 on ebay. They can be had for pennies on the dollar and you can do a lot with them. I wouldn't go older than 2016 because those tended to have a lot of power draw and heat. Then I would use ECC RAM if you intend to use as a NAS.

If I were you I would not host Jellyfin publicly. Please use a VPN like Tailscale or ZeroTier. If you feel particularly intrepid you could try using Nebula for your VPN platform which is completely open source and free. I am in the midst of using Nebula to build out my own software-defined overlay network.

An old gaming PC is not inherently much worse than any other system as a simple server. If you want to save money, you can just keep using it, but it might be worth reducing the power consumption.

You could start by removing or disabling unnecessary components:

• remove the GPU if it's not in use
• go into your BIOS and disable anything that is not in use, such as PCI Express slots and USB slots

This can significantly reduce idle power consumption.

As a next step, you could install Linux, which may reduce idle power even more by using fewer system resources.

But all in all, there is no better solution to your heat problem than to move the server to another room. Even my Raspberry Pi and router together produce a noticeable heat in my room.

For reducing power consumption (and thus heat), a simple improvement could be just switching to a headless Linux install instead of Windows. It'll run much more efficiently for homelab workloads.

Since you already have a UDM, I'd suggest just a simple port forward to expose your Minecraft server to the public internet. Yes, it will expose you to risk of attack by having anything public from your network, but as long as you keep your Minecraft server up to date you should stay covered security-wise pretty well. I'd suggest setting up a cronjob to restart the Minecraft server and check for updates every 24hr to make sure you're always up to date.

What are the specs of the machine? How hard is it working to run those services? Both of those could be run on a raspberry pi for low usage but then you need to learn linux if you aren't already using it.

If it's under powered and working hard all the time it will draw more power and generate more heat.

Does it need to live in your office?