Relationship between Python and Platformio IDE under VSC?

Hello everyone, sorry to bother y’all but my 3d printer is a brick until I can get this motherboard replaced. Please help

Long story, latest chapter:

My specific question here: Why can I build the Marlin firmware after over-writing the files for my printer but when I change the board definition and delault_envs it fails? It appears to be looking for files and not finding them but I am not even sure of that let alone why.

More specifically, II am being told that maybe I need to re-install python. Even if that works, I sure would like to understand wtf is going on. It makes no sense.

More likely there is something wrong with my changes but I really really thought I understood what was going on. I really like understanding what is going on. That way I can help others with the same problem in the future. Most of the answers I see on Reddit, not just to my own questions, are of the form “try this, it worked for me” and not “here is what is going on”.

Please help, my life is kinda on hold until I get my printer going again.

Per this you seem to have solved it already.

Thanks for the reply. Yeah, I reinstalled Python and it worked. But why?

It is a “try this, it worked for me” solution. I was seeking understanding but oh well.

It seems to me that difficulty with firmware is in general holding back the hobby. I was thinking that I could help the next guy better if I understood what was going on.