Okay, so Thanos car has the range advantage as he can pull of a surface wipe with the Power Stone, and he could bring The Ancestor to him by manipulating space with the Space Stone which is a bad idea or just throw meteorites at him instead.
The Ancestor, however, just needs to get close to him and make a simple gesture to flay him. Type 8 immortality helps against any death that he'll experience, and I doubt TA will die during the fight. Not voting yet.
Or he'd say "SOMEBODY TOUCHA MY SPAGET" and spegetify Ancestor
Even though for a lot of the movie he either energy blasts people or punches them, neither of which will do all that much to the first phase of the Ancestor who's kinda completely invunerable to... Fraction of 2.8 Ninaton attacks
Ancestor FRA, sure Thanos has a huge metal glove that hinders his arm movements but he's got the M U S C L E S to lift it easily, it's just that he needs more than raising his hand to kill/incap Ancestor. Ancestor just raises his hand while Thanos raises his hand then clenches his fist. Clearly Ancestor is faster.