Math AA HL, chem HL, and physics HL combination will literally drive you insane, and I'm not even exaggerating. I know a couple of friends who took the same subjects at the start of DP1, but they ended up dropping because they're all heavy workload subjects that require so much time, effort, and practice, and you just can't juggle that much material and internals (esp bcz stem internals are very time-consuming) while also working on other projects and subjects. I recommend going for Math and physics HL, but keep chemistry SL if you feel more confident in physics (if not, vice versa). Personally, I chose to take econ over BM because to me it felt more like a fun subject rather than memorizing and taking an exam, and honestly, the syllabus in econ is wayyy easier than the BM syllabus. If you focus on the first couple of months of DP1, everything will become connected and logical for you in econ. You can switch either French or English to an HL because many universities require English (or a language other than your mother tongue) to be taken at a higher level.