I know this is beyond the scope of your question but you are at a very similar place like i was over a year ago.

For the reverse proxy you want ingnx manager and it will handle all of your reverse proxies just fine.

But what i really want to recommend is to change up that debian into proxmox,

Proxmox is a debian based efficient server OS. Basically every service you run now can Easily be run as its own isolated container with very little overhang.

Best of all there is a community for Helper script that will install entire services including Nginx but even nextcloud from a single command.

https://community-scripts.github.io/ProxmoxVE/scripts?id=nginxproxymanager

I highly recommend you try proxmox to get the most potential out of you system. Basically can run many services and vm with little overhead, dynamically sharing the specs.

Now about those specs… what everybody else said really but heres some pointers:

You don’t need a big dedicated gpu unless your doing something that explicitly demands it. They are tricky to setup with virtual machines also.

If you plan on running a minecraft server i recommend at least 8gb ram. Most will probably run fine on 4. You can probably run quite a few things on 8gb but ram is cheap and its nice to have some extra room.

For cpu, the more things you do the More sense it makes to have more cores. If you plan on buying then amd ryzen x y z is you best option where.

X is the number you want higher Y is a number you should not care about as much Z is potentialy the letter “G” for graphics, they are often more expensive. Get them anyway because now you dont need a dedicated gpu (and even if you already own a gpu. Trust me you will thank me if that one ever has issues)

If you really want me to draw you something decent up that will give you plenty of freedom to experiment.

Ryzen 7 … G, 32gb ram. Small ssd for os. xTB of performence HDD ideally configured as some raid in proxmox.

It still cannot be said often enough that a (well cared for) second hand unlabeled laptop running ubuntu is all what most people need when they start pondering about home servers.

Not sure either but one of the important chances is that Dash (Dynamic Adaptive Streaming over HTTP) is being replaced with a newer system on YouTube.

There are some good innovations in the replacement but its much harder to implement.