It clearly says she's using her hex powers here, not telepathy. She's targeting the gamma cells in him to combine all the different Hulks in him into one, not mind-controlling him.
Jean already used her telepathy on the Hulk to get rid of the Banner personality in 1996.
Girl… and don’t get me started on her being debuted with TK and TP rather than hexes and probability influence and ESPECIALLY don’t make me get started on that wandavision storyline. CUZ ALL OF A SUDDEN ITS MINI SKIRTS ITS MINI DRESSES ITS BIG CHUNKY BOOTS LMAO.