Even adults need a certain amount of adaptation after a vacation in order to return to their usual “work” routine.
The child needs this too.
The thing is that after the summer holidays the usual routine gets disrupted.
If you allow your children to stay up later than usual in the summer, you should stop doing this a couple of weeks before school starts. This will help them get back to their normal routine faster.
Therefore, set your lights out time at the same time as during school hours.
In the summer, children eat differently than usual because their busy schedules change. So parents should return to their usual meal schedule.
The diet should also be made more familiar.
In order for the child to understand the "reality of what is happening" faster, it is worth involving him in preparation for the school season. Study new subjects, buy all the necessary stationery, make a rough plan with goals for the next school year.