Old-school method of a Pupil Shared drive, mapped as 'P' is the tried and tested method.
It's a free-for-all for students and teachers alike.
Staff should set a folder per intake with Year Of Leaving (easier than Y1, Y2, etc, or Year of Intake I find)
In that folder, each kid has their own which travels with them through their time at school.
So, Computer | P drive | 2026 | Bob Cheese | Y6 | files
I guess their Home drive mapped through GPO works too but then the staff need to navigate to multiple home folders and that's a faff they won't want to do.