Selfhosted

First, a hardware question. I'm looking for a computer to use as a... router? Louis calls it a router but it's a computer that is upstream of my whole network and has two ethernet ports. And suggestions on this? Ideal amount or RAM? Ideal processor/speed? I have fiber internet, 10 gbps up and 10 gbps down, so I'm willing to spend a little more on higher bandwidth components. I'm assuming I won't need a GPU.

Anyways, has anyone had a chance to look at his guide? It's accompanied by two youtube videos that are about 7 hours each.

I don't expect to do everything in his guide. I'd like to be able to VPN into my home network and SSH into some of my projects, use Immich, check out Plex or similar, and set up a NAS. Maybe other stuff after that but those are my main interests.

Any advice/links for a beginner are more than welcome.

Edit: thanks for all the info, lots of good stuff here. OpenWRT seems to be the most frequently recommended thing here so I'm looking into that now. Unfortunately my current router/AP (Asus AX6600) is not supported. I was hoping to not have to replace it, it was kinda pricey, I got it when I upgraded to fiber since it can do 6.6gbps. I'm currently looking into devices I can put upstream of my current hardware but I might have to bite the bullet and replace it.

Edit 2: This is looking pretty good right now.