Monica has already phased through Hulk once before, so there is evidence she could render herself immune to his physical attacks. She actually would have reverted him back to Banner here, but extenuating circumstances stopped that.
https://postimg.cc/gwYBq9pd
https://postimg.cc/kVfYTjMS
She's also jumped inside She-Hulk as gamma energy, although she did it to power Jennifer up.
https://postimg.cc/LY5Cwzhb
https://postimg.cc/9r7Sct13
Originally posted by carver9
If she had the ability to solo Hulk, they just would've brought her.
Not necessarily true. Comics often ignore easy routes to victory for the "sake" of story. I put that in quotes because a good writer shouldn't have to rely on a character just standing in the background to avoid addressing the obvious ace-in-the-hole. If you're going to make a team lose, there should be a plausible reason why it happened. That's part of what made Uncanny X-Force(under Remender) so great. Wolverine and Deadpool never had their healing factors neutered. Fantomex and Psylocke didn't stand around like idiots when a misdirect or tp assault would work. AoA Kurt would port your face off. Whenever they got countered, it was always a very plausible reason, like Dark Beast's tech.
None of their defeats ever ended with you going "Wait, why didn't so-and-so try doing this? Why did they just stand around?" You could feel their desperation because they were trying their hardest and failing, believably.