You're lucky to have kinda the opposite of my situation.

I used a second hand office machine with a low power graphics card added, because that came out quite cheap. Until about 2 years ago, when I saw that really good looking cases, with the glass and LEDs and everything, are quite affordable now, got one for 60 bucks, I think.

The problem was that that office machine was not made to be upgradeable. Power supply that delivered pretty much exactly what the current parts needed and no more, with custom connectors to the mainboard.

So I thought ok, I do it in steps, after all that's the whole point that that's possible. Start by getting a nice modern bequiet PSU, and finding a more standard motherboard, that fit with my CPU and RAM. In some obscure webshop no less, because stuff is old, I'm working with DDR2 here.

And the plan was that later I would look at upgrading motherboard+CPU+RAM, because I'd have to do those together.

And then the data centers happened.

I'm just lucky that the old machine was a beast for its time - the back then impressive 16GB RAM are still decent now. Battlefield the WW1 one ran fine, that game where you upgrade your jeep was too laggy - gotta be a bit more selective about what I run now, because my upgrade plans are on ice until we storm the data centers.