Thx all for your replies!

I think I'll just do it the chill way and watch GPU prices the next few months. So I can build in a second GPU
in my gaming PC first with a new PSU and then try to maintain a more casual setup so I won't get charged with insane
electrical costs if they find out and charge me the extra I used.

Also I calculate the electrical costs of my city and try to assume what the company pays for it, so I know that I can afford it if they ever come to my appartement and want me to pay what I used extra.