You can’t complete the guest relations quest because you can’t see the squirrel if you didn’t finish BfA and you can’t finish BfA because there’s no Rastakhan on the throne. And you “know about this bug” for the past 7 months.
Can’t See King Rastakhan to Turn in Quest - Zandalar Forever! - Blizzard Support
Amazing “game” blizzard keep those $90 mounts coming. Cringe company.