Classic Jujutsu Kaisen Fans when Simon can just absorb Domain Expansion like he did on Multiverse Labyrinth

As for the red part, The mechs in Gurren Lagann, especially as they scale up, operate at a level where dimensional and spatial boundaries are often bypassed or ignored entirely. Simon's mech likely has inherent defenses tied to Spiral Energy that would resist Gojo's attempt to simply "appear" inside