@csehz That is a problem that occurs many times.
In this case, the keyhole looks fine.
But to make it smaller, one way is to apply the Mirror Modifier. Then fill the keyhole ( ‘F’, just an N-Gon is fine). Press ‘I’ to inset.
‘X’ to delete the Face( the N-Gon). You can get rid of the ‘outer keyhole vertices’ by merging them with the inner ones, if that makes sense;)
Now delete one half of the mesh and give it a new Mirror…
Maybe there is a better way to do this, but in this case this will work.
