I wrote my first AP English thesis in high school on this exact issue: students being assigned too much homework and the detriment it caused them. I don't remember the source, but an academic paper from around 2010 (I wrote the paper in like 2012) talked about how assigning more than 5-10 math problems per night could cause way more harm than good.

Not only was it incredibly time consuming for people who likely had sports/music/jobs/family obligations/etc, but it reinforced incorrect learning habits. Basically, if you were given 100 math problems, but didn't understand how to solve them correctly, you'd just be reinforcing your mistake 100 times. Add in the fact I never had a teacher who would spend an entire class going over all 100 of them, and kids were basically learning the wrong way every night. Plus, at least in my experience, the assignments were turned in and then the class moved on to the next lesson, and by the time you were given the graded assignment back, you were already 3+ lessons ahead, still learning everything wrong because the foundation was built on sand, not stone.