Sometimes, I colab with friends, and we each do our part on a separate project (because if you do it on the same one, you have trouble saving) but then it is difficult to import them. Either you put each sprite and backdrop and code in the background into the backpack and paste it in (which gives you problems) OR …. nothing. So, the suggestion I guess is to be able to completely import one project into another, and all the global variables kept global.

I don't know how variables are affected, but you can download any project and upload it in another (under file there are options to do so)