They move too fast. This is the problem with a lot of monsters these days. They no longer have that creepy/unsettling feeling of being trapped in a room and something very slowly is moving towards you and there is no escape (this is why the 1979 Alien scene of the Alien slowly reaching out the Lambert is so shocking compared to the fast Alien in Alien: Covenant which was not scary at all).
Set in the Mummy 2017 had a perfect walking pace. This is what I want to see more of when it comes to monsters in movies.
The perfect filmic monster wouldn't even have to move at all.