Looks like you have a bunch of overlapping faces (the red specks in the second image) and on the far right indent something is very wrong with the faces where you can’t see the lower edge. You definitely have some double vertices, possibly happened during an extrude operation. In edit mode switch to vertex mode -> A to select everything -> M -> Merge by distance.
Looking at some of the faces and edges though, this might not solve all your problems. In that case your best bet would probably be to start and redo this section over from scratch.
