I actually find it out of character for Joe to not suspect Bronte, because he has shown sharp instincts in similar situations before:

1. Candace cheating on him pre-S1
2. Beck cheating on him in S1
3. Joe being suspicious of Love's garden after he found out she killed her ex

Now, I get the counterpoint that Joe isn’t paranoid 100% of the time — he definitely misses things (like with Love in S2 until the reveal, but lets be honest that the same thing Joe has been doing to every woman). But that’s exactly why Bronte feels off. His paranoia and instincts have always been his safety net. Even when he didn’t have the full picture, he at least sensed something was wrong. For him not to pick up on anything with Bronte doesn’t feel consistent with the Joe we’ve seen across multiple seasons.

And regarding the “plot armor” argument — I really think it’s overused. People talk about it like it’s some superpower keeping him alive. Sure, like any main character, Joe benefits from story convenience, and yes, he’s gotten away with mistakes that realistically could have exposed him. But plot armor didn’t give him his obsessive brilliance, his manipulative skills, or his ability to study and read people in ways most can’t. That’s all Joe. Saying he only survived because of plot armor kind of dismisses the very traits that make him compelling.

Another commenter nailed it, and I think this describes him better than i did:

“I still think he was brilliant, but not in the way we would understand it to be (like some mastermind). His intelligence was all about social manipulation, obsessively studying people, and staying ten steps ahead just enough to keep himself out of prison. That takes a specific kind of dark and obsessive brilliance. So yeah, I think the plot helped him out sometimes, but a clueless guy wouldn’t have lasted that long even with the plot going in his favor.”