Well, Graphite solves the problem of how to keep your stack of GitHub pull requests in sync while you squash merge the lowest pull request in the stack; which as far as I know jujutsu does not help with.
This is something GitHub should be investing time in, it’s so frustrating.
I've been going through a lot of different git stacking tools recently and am currently quite liking git-branchless[1] with GitHub and mergify[2] for the merge queue, but it all definitely feels quite rough around the edges without first-party support. Especially when it comes to collaboration.
Jujutsu has also always just seemed a bit daunting to me, but this might be the push I needed to finally give both jj and tangled a proper try and likely move stuff over.
The problem however lies in who or what does this rebasing in a multi-tenant environment. You sort of need a system that can do it automatically, or one that gives you control over the process. For example, jj can often get tripped up with branch rules in git since you might accidentally move a bookmark that isn't yours to move, so to speak.