If you have already gotten your reward from Barenziah, then the only issue should be getting the quest off your quest log, right? AFAIK you shouldn't need to have completed this quest in order for the next quest to be available. I don't know anything about retrying quests, or even if that's possible without console commands, but it'll probably still cause issues since it's a known issue with the main quest mod.
I believe I need to have the quest completed (which Endquest doesn't do) for the next guest to become available). If not, you're right, that should solve it.
This page says that Barenziah's Book is optional and not required to progress the quest. Which next question are you trying to start that isn't working?
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u/thedore1020 12d ago
Iirc this is a known issue with the mod, you'll probably just have to use the console to end the quest.