How to do typically avoid the necessity to rebase a WIP branch after every other merge on the default branch?

Requirements engineering: split tasks into smaller tasks, trying to avoid long-lasting feature branches being worked on for days or even weeks while other stuff is going on.

There is nothing wrong with rebasing.
GIT makes it super simple and if your code is properly organized, you most often don't have to resolve any conflicts.

Feature branches existing for weeks are totally fine too. Just don't forget to rebase before the final merge...

So it turns out I am assigning myself the only role that requires these rebases. I am the one who does all the low-level refactoring, CI definitions, shared utils and common codes.