I am thinking a little bit about buying Raspberry Pi, but I am not sure what to run on it. I am a webdeveloper, so I was thinking about server, but I would appreciate if you gave me some ideas.

I have mine as a retro pie on one SD card and raspian lite with pivpn and pi hole on the other

I got an idea, but I dont know if its even possible.
Now, like 99% of time I use my laptop to code, but I am gonna buy some amazing desktop after Christmas. So I was thinking about buying Pi as a server, so that I it would be easy to switch between laptop and desktop while working on the same project.
Is this possible?