It's boring AF period because any kind of mind control or hypnosis strips away 100% of her agency. Worst yet when she doesn't remember anything after the fact, so there can be no type of growth in the relationship or corruption. Even if she's not a mindless slave and she's enjoying it, she's still just an extension of the guy's will. You might as well be watching him jerk off at that point, because she's not a participant in the sex.
Someone didn't play a good hypnosis game it seems. For example here's 2 scenarios.
1) let's take Kyuukon Saimin game and it's premise of a successful businessman who practices hypnosis and want to go for certain girl, daughter of one of his rival companies (who also has a boyfriend, so netori). He buys in position as director in her school, and through blackmail setups a situation where she needs to visit him every day for a hypnosis session. She has natural mental resistance and he have to play a slow game to break her barriers. For example first introducing her a complex about her "Bad breath" which she then need to check with him. Which through sessions transforms into kissing, then into her fear of her body odor (which leads to undressing) and so on. Perfectly executed slow corruption though hypnosis. And there more twists like that in that game.
2) Or maybe Saimin Gakuen by Fudegaki soft, where guy finds a hypnosis gun and uses it to get in as a teacher into all girl's school. There is a lot of interesting scenarios. For example how about when he used it to link all 5 major senses (Remember when you ate most delicious thing, heard most beautiful music, petted softest cat etc) to stuck up rich girl's asshole (while she is unaware) and then proceeds to remove hypnosis and only leave restriction that prevents her from running away. Followed by round of anal play where she do not understand why a finger up her ass feels so good. (He adds more stuff overtime, and there are different routes with different girls, but he mostly keep their personality intact while adding some weird behavioral twists that break them overtime.)
Or from the same game where he bends a nerdy girl's perception to make her think that a plush cat he bought is magical girl mascot (he erased her perception of himself and talks and moves the cat). And that mascot is here to make her into magical girl (He even makes a magical girl transformation sequence for her, by freezing her perception and dressing her up so she thinks her clothes are just magically appearing). He then proceeds to make her fight "Monsters" (usually pretending to be the victim and needed being saved by some sexual act)
I can go on but there are many good hypnosis games most of which are not translated (like the 2 i mentioned above) and even then fetishes are there for a reason, if you fail to understand them - it means they are just not for you.
