Look.  It’s not that complicated.  There’s basically just one rule you have to follow in order to make a decent giant-monster movie:

Every monster is a character.  No monster exists only to smash stuff.  If it’s worth dedicating screen time to watching it rampage, it’s worth dedicating screen time to giving it some shred of personality.

Toho figured this out in the ‘50s.  I don’t understand why American studios seem to find it so incredibly difficult.