Full Disclaimer: I can't be bothered to go through all the security steps to host this (also Heroku free plan is gone,) so you'll have to host it locally on your laptop, desktop, pi or something. Also there's no user accounts or anything, so you'll have to set that up AND go through the security steps here. If you do end up setting something up, it uses this template.
Anyways, it keeps track of Events, Homework, Assessments (and their subtasks) and Subjects.
If you want to host this from a mac running MacOS 12 or later, you can use the following shortcut: