Definitely check with your GC about how this affects the “most rigorous” box. Do you have an idea of what universities you want to apply to? If they’re ones that don’t need the “most rigorous” box checked, you have more flexibility in the classes you take in 12th grade.
If you’re looking for college credit for IB classes, some schools give ZERO, some only give credit for HL classes where you earn a certain score (5+/6+/7), and some will give you almost enough to be a sophomore in credits. And as far as that goes, AP scores are treated the same way. Do a google search for “school name IB credit (or AP credit)” to see what that school’s policy is.
By the time you’re applying for colleges, a year from now, you have no idea if you will be getting the IB Diploma. Generally, you don’t know about the results until after graduation, which is after the deadline to commit to a university. All you can say when applying is that you’re an IB Diploma candidate. Schools will be looking at the rigorous course load you’ve had up to that point, and will be making acceptances based on what they see you’ve done from 9-11th grades, and some may require autumn senior grades. I’ve never heard anyone from a college say that they view IB classes any more favorably than AP classes; in fact an admissions counselor at a Cal Poly SLO this summer didn’t even know what IB was (much to my dismay).
I say this as having received an IB Diploma decades ago, with a current 12th grader who is working on their IB Diploma – you pursue the IB Diploma because you want to, because you want that particular challenge and feeling of accomplishment. Quite frankly, taking AP classes will likely serve you just as well for college admissions, as long as an AP schedule is treated as “most rigorous” by your GC. My kid’s school only checks that box for IB Diploma candidates and they were clear about that in the IB interest meetings held during 9th and 10th grades. Ironically for my senior, as their college list has been winnowed (based on majors, school setting, etc.), one of the more attractive schools is turning out to be our state flagship which couldn’t care less about the “most rigorous” box. But that box will be important for all their reach schools.
Since your parents wanted you to take Chem perhaps they would consider hiring a tutor to help you with that this year? I think it’s early enough in the school year that whatever concepts are tripping you up could get cleared up quickly, so that you’re not continually feeling like you’re making up lost ground for the rest of the year. And there’s also the chance that you end up “getting it” and decide Chem HL isn’t the worst thing ever.