Eh, basically killing your pregnant wife who you’ve been trying to save the whole time and then getting your limbs hacked up and set on fire by your best friend has got to rate at least as high on the trauma scale as your mom getting killed by Sand People. He went through some shit on Tatooine, but Mustafar is where he went full Vader. Plus, Mustafar is a much radder place for an evil lair.

These are in-universe explanations, of course. I think we all know the main reason he didn’t hunker down on Tatooine is that it would be impossible to make that work with the rest of the existing material.

EDIT: I misunderstood, I thought you were suggesting he should have built his digs on Tatooine. In the canon comics he actually does go back to Tatooine shortly after the events of ANH and slaughters another village of Tuskens just to kill time waiting for Boba Fett to meet him.