Ctrl + Shift + A - SLRPNK

I dont really know photo editing, could someone explain?

It takes a while to figure out how selections in Gimp work.

It whenever you select you have created a mask and when you combine it with layers it can get very confusing.

If you accidentally select a small bit you cannot edit anything else. I think that is what OP is referring to.

There is a tool that shows you what you have selected that can help.

IMO Gimp isn’t very well documented so you can get stuck for a while before you understand what is going on.

Oooh, wait, that isn’t how it works in other programs? I really like that behaviour in GIMP to be perfectly honest, have used it in editing stuff deliberately.
Same… I think Photoshop would probably feel difficult to me to get my head around at this point since Gimp’s workflow is the one I’ve known and used for over a decade and a half now