The difficulty of an AP course in most subjects (getting a high AP score) and time required is aligned with the school districts preparation beginning in middle school. Ask current honors and AP students at your HS. For districts with robust math programs the weed out class is Algebra 2. Only those capable of a high AP score move on in the BC track. Those students would rank their Algebra 2 experience as more challenging and stressful than AP BC. AP Chemistry and any foreign language are similar.
With a lot of reading for history, biology and literature, are you a proficient critical reader? That will save you tons of homework and study time.
Everyone ranks AP physics E&M as difficult for good reason. Most enginneering and physics students take it again in college.