If you want to win fights by martial means then you would be correct that keeping slut level and desires low would be desirable. This however is a very hard way to win the game as the game goes on as there are plenty of ways to gain passives that would make such a build progressively harder to play over time.Thanks, that was still a bit of a grind to deal with. The game is imbalanced. You need to keep your slut level low in order to be able to advance and clear floors but that means you have to work at it to avoid lewd content.
If Karryn has sexual skills used on her enough time she gains the ability to initiate it on the opponent instead, filling an enemies pleasure gauges causes them to orgasm and most enemies will leave the fight. Some stronger enemies may need to orgasm multiple times to get them to be defeated.
Karryn is at her weakest during the transition stage between these two states, when she is corrupted enough that she struggles against inmates in straight up fights yet is not corrupt enough to be able to defeat them easily sexually either.
Given you do not seem to be wanting a challenge run (given the complaints about difficulty and all) I would recommend working your way towards a slut build by trying to let enemies use sexual attacks on you enough times. Do this and you will be able to start working on actively corrupting Karryn, the quicker you get her to a more corrupt state the easier time you will have in the long run rather than trying to proceed with what is essentially a challenge run.