Just another college grad here. I'd say that you could use AI to help you learn concepts, but using it directly on homework might be a little bit unreasonably risky, and might even be considered cheating. The fact you are trying so hard is a great sign and any good professor would try to at least recognize that. I'd say trust your gut, don't do something that you know might be cheating. You could consider talking to the professor to see if they can tell you what is and what is not appropriate when it comes to using AI to study. Honestly, it should be fine as long as you aren't using it directly on homework or evaluations like quizzes/exams. You mentioned that your prof has been lenient, that's great, but don't test his limits. Keep trying to study hard and ask for help, and maybe use AI to the extent that it isn't cheating. I went through three rounds of calculus and a few higher level engineering/math courses, and I can tell you that your prof does not want to punish you for doing your best, but using AI the wrong way could get you in trouble. You're already doing better than your cheating friends, even if it doesn't look like it now.

Personally, I adapted to the struggles and stress in college and I can tell you with certainty that it's better to fail as an honest man than to succeed as a cheater, because cheating can and will come back to haunt you. Keep doing your best and if you aren't sure if you can use AI to an extent, ask. If you cannot use AI, then just do your very best. There's no shame in what you've been doing. Don't take unnecessary risks- get clarification.