I think there's merit to that idea. I think Ian has grown resentful of Ethan over the years. If you think about the paths they both took, they were largely similar but one ended up successful and the other has largely failed. Ethan's pivot has him hosting a widely successful podcast while Ian has nothing. I have to think that over time Ian feels like he's done everything right and unlike Ethan has nothing to show for it.
Then over the years you see how Ian could take Ethan's help as Ethan "big-brother"ing Ian by trying to help him out. Help that Ian might feel is patronizing and makes it seem like he can't stand on his own two feet. All his success over the years since his 'troll's remorse' episode has come as part of Ethan helping him out.
He probably feels like he's in Ethan's shadow and like his bitch. Hence why he felt it so necessary to betray Ethan to show that he could stand on his own two feet without Ethan. To be a redditor for a second, it's like in Akira when Tetsuo grows resentful of Kaneda for always having him bail him out. That's Ian.