The installers gave me a window unsealed on the outside but sealed with a rubber seal on inside around the frame (windows are uPVC).
After rain, the damage was done to walls by leaks and the rubber seal inside was blocking the exit for the water so I pulled it out. Unfortunately I'm unable to put it back in place as tight as it was, it's become completely loose after fitting in gap.
The windows are installed on uneven wall opening so there is expected wiggle room.
I prefer to do insulation myself since installers completely disregarded this. Should I try to re-fit the original rubber seal or glue it on, or caulk even though the window wiggles? Ive seen videos where people caulk the rubber seal? Here's some of the damage, bubbled paint: