For example with Opigno you can already build an open-source based education platform with content authoring with H5P[2] (HTML-5 based interactive content)
I've used Opigno LMS in the past, it's Drupal based so it's easy to deploy/maintain and basically have all features you advertise. Schools especially may use a learning platform for 10+ years, at least when authoring with H5P they are not stuck in a single platform anymore. What's your solution for this problem?
The loss of flash left a lot of courses or interactive learning content unusable, that's a mistake I hope new platforms don't repeat.
[2] https://h5p.org/