Potential ethical concerns on advisor's advice on publication venues
In essence, you're peddling in conspiracy theories: You're claiming some dark motive in your adviser's response for which you have no real proof. You also claim that he might sabotage you, without actually having any concrete evidence nor do you show any reason why he might do so. Moreover, your adviser actually gave you three quite sensible reasons why he thinks that your current plan isn't good that you dismiss out of hand.

Here's the thing about life: If (i) someone says something that actually makes sense, then (ii) that's usually what is actually the case. In your case, I very much believe every reason your adviser gives you: It genuinely is hard to write a paper in 3 weeks; I'm going to claim that it's impossible. If he says that the journal generally published a different kind of paper, that's something that can be checked by why not just believe an experienced researcher and author? And finally, if the community is small, you do risk running into the same reviewers and your adviser is correct that there is a stigma attached to having reviewed someone's half-finished manuscript. Nearly every other statement by your adviser in your question also seems totally reasonable to me.

So I see no good reason to believe any of your conspiracy theories. I think you fundamentally need to adjust your assumptions about people indeed meaning A when they are saying A.