Based on our experience of D13 and S16, 3-4 hours per night of homework for a full schedule of AP/honors classes is about par for the course and can be manageable for many kids even with ECs. It really depends on the kid (and family expectations for time for family commitments).
My D attends a top 30ish LAC (and got into a higher ranked LAC as well). She is a theatre/singing kid and took advanced/AP track in English/Social Studies but dropped down to honors track in science, math and Latin. She was an A student with a few B’s sprinkled in (ironically, usually in the easier honors classes because they were in areas not her strength). She also had advanced/auditioned choir and advanced theatre class every year. Her ECs were demanding: competitive figure skater, theatre, an outside a capella group, voice lessons, and a regular volunteer commitment. She very rarely did homework on Friday or Saturday nights but typically spent almost all day Sunday on homework. And her sleep really suffered. She managed to be in bed by 10 or 10:30 through 10th grade but after that, forget about it. Midnight was more normal (even with leaving the house at 5:30 a.m.). That schedule was tough but she really enjoyed all her activities and it has set her up well for college where she is arguably even busier. And she apparently doesn’t sleep at college either.
D16 has a full AP schedule. He is more math/science oriented (AP Chem, AP Bio, AP Physics, AP Calc BC) but stuck with AP Lit and AP German this year. He also did AP US, AP Econ, AP Gov. His grades are also very good although he has had 3 or 4 Bs through the years. He is in a fall varsity sport which takes up a lot of time in season, and on club team winter and spring (which is less time intensive for practice but more time on weekend for games). He also plays an instrument and is in marching band/takes private lessons. But other than that, he doesn’t have big EC commitments. His top college choices are ranked in the 30s and we are hoping that his relatively weak ECs won’t hurt him. He spends a lot of time on homework but doesn’t complain very often. He just sees it as part of his routine. He is sometimes up pretty late but normally is in bed by 11 p.m. or so. This year, once fall sport is over, S has a part-time job lined up.
Neither kid ever had a study hall. It was too hard to fit in schedule with the theatre/music/band classes (and for my son, both AP Bio and AP Chem are double periods since there is no pre requisite year of the subject prior to the AP class).
Our HS does not do +/- so an A- counts the same as an A and both my kids learned to prioritize their work (especially in subjects they didn’t love) to do enough to get the A- but necessarily killing themselves to get A or A+.
Again, this might seem like a crazy schedule but it has worked for my kids and is pretty typical of the top 10% (at least) of students at our public HS. I do think it’s hard to ratchet kids back from the norm. But there are plenty of kids at our HS who had good grades in all CP/honors courses and less EC commitments and decent test scores who ended up at perfectly fine (and better than fine) colleges including our state flagship (although students from our HS generally have to have at least a 3.8 W GPA to get in these days).
I would listen to your kid and keep letting her do what she can manage without sacrificing her health (either physical or mental) and whatever level of commitment/attendance you deem appropriate at family events.