There's a difference between known liar Trump, who contradicts himself from one sentence to the next, and Kamala, who is a bog-standard politician. This is just a hypothetical of course, but I think it'd be incredibly likely that Kamala would have continued economically suppressing Iran via sanctions, maybe some half-hearted attempts at another nuclear deal, but would have had advisors presenting what military aggression would mean for the region (including the economic damage of them blocking the strait) to prevent her from pushing this far. She'd likely be another Biden: not directly assisting Israel in aggression, but too cowardly to call them out in any meaningful way.
Anyone with a functioning brain could see Trump was talking out of his ass on this topic, especially when project 2025 explicitly talks about waging a regime change war on Iran and assisting Israel in bombing Iran.