One of the limitations with the organization of conventional education is the assumption that learning only occurs due to teaching by the teacher (Direct Instruction). While it is true that most Formal Education is delivered that way, much Learning occurs through other means - from peers, especially when there is diversity in the group.
Working and playing in mixed-age groups is an especially powerful tool for this, but unfortunately the conventional school system limits that to so-called “co-curricular” activities. We can have periods where students are mixed up (e.g. students from Grade 6,7,8 are mixed) and provided opportunities for various self-driven activities.
This could be a community engagement project (ශ්රමදාන, දන්සල, etc), the Next eගෙනුම | Current Affairs / Critical Thinking proposal, a book club, a school garden project, etc.