The two "Public x" define different variables, not references to the same
one.

Leave the one in UserForm1 as it is. Remove the one from Module1.

A compile will now give you an error because x is not defined  in Module1.
This is correct  and shows  you that Option Explicit is doing its job.

Now, use "dot" notation in Module1 to access the x in UserForm1:

MsgBox (UserForm1.x)