Hi there ExaSamer,
We understand after sorting and organizing your apps in LaunchPad, they revert to the original layout after restarting your MacBook Pro. We're glad you've taken the time to connect with us here in Apple Support Communities, and we can provide some guidance.
To begin, does the issue persist when your MacBook Pro is in safe mode? Learn how to use safe mode from this support article:
How to use safe mode on your Mac
Next, have you had the chance to test the issue in a new user account? If not, give that a try and let us know your results. The support article below provides step-by-step instructions for creating a new user account:
Set up users, guests, and groups on Mac
If the issue persists, you'll want to connect with Apple Support directly for more help. This link will help you get started:
Contact Apple Support
Take care.