I mean you say this but as a dad of a kid who had to miss significant parts of the first semester of school last year due to a medical issue, I had to do a shitload of extra work to keep her both off truancy reports and credit for attendance efforts so her schoolwork would actually be accepted and she could continue in her grade level. She even got dinged for actual excused medical absences that she had valid reasons for missing classes/days of school in the spring semester based on how much time she missed in the fall. I was possibly facing appearing before a truancy court if the school didn't step in to help us out. This is Dallas ISD so maybe Austin doesn't give a shit but they definitely do here.
Maybe my kids schools are different but there's a ton of work and missing a day can be really hard in terms of falling behind for my older one. You can only make up stuff in after school sessions for tutoring. If you miss a test, you can make that up but it can then be an unexcused absence for the class you're missing to do it. If she doesn't have a note, she can't make up the tests, homework, or gym classes. We learned that the hard way this fall. Granted, this is a magnet school so maybe that's more the reason but my older one never had this much work before getting high school. If anything, middle school did not prepare her in any way for all of this.