My game is written in C++ and SDL. I wrote it in a linux computer so I already have that executable but I dont have a way to compile it to windows. I struggled for a while with cross compilation and even tried compiling for webgl but couldnt get anything to work. What should I do?

Upload the game for linux for now then you can upload the windows build when you have it using a vm.

I'll play the linux build - hopefully, enough of us can get it reviewed.