You head to the farthest branch in the chain, fetch the latest main, and run `git rebase --update-refs main` (I prefer interactive mode myself) and then force push all of the branches from start to the end.

1: https://git-scm.com/docs/git-rebase#Documentation/git-rebase...

Before this feature when you were doing it manually, it was a huge problem. One of the points of this feature, is it automates rebasing the whole stack.

Rebase the stack onto main.

you just rebase it? what's the big deal?

I don't use Github but I do work at one of the companies that popularized this workflows and it is extremely not a big deal. Pull, rebase, resolve conflicts if necessary, resubmit.