[DAV ACT 2 SPOILERS] Regarding a specific main quest and soft-locking sidequests

I'm currently getting started at the Siege of Weisshaupt quest - not sure if this is Act 2 yet or if it's still Act 1.

I was wondering if doing this quest locks you out of side quests, like the Save Minrathous/Treviso quest did. I have some side quests I want to do later (specifically Kal Sharok with Harding), but can't wait to get on with the main quest because I'm just so invested in the story at this point :)

Hoping anyone can answer this and help me out.