Hi Jonathan,
You have a few problems. First let’s do some clean up: you need to fix the overlapping Faces (a leftover from your earlier Inset with the wrong Selection, I guess):

That is one large Face and two smaller ones. get rid of the smaller ones..if it is difficult to only Select the two smaller ones, just Delete all three and the re-fill the bottom with one Face.
Make sure, that the large Face is not like this:

But Fill it with this Selection:

Then Merge By Distance and lastly fix the Normals.