In this particular video, I notice you have a very small space to your door trim so much that you cut some of the trim out to fit.
Mine is similar.
Since I am ordering a custom size pre-hung door anyhow, I was thinking that I would add two more 2×3 (that’s what mine are) to make the doorway smaller so that I have more space to tile and space for door trim and space for door hinges and space to open the door. Does that sound like a good plan? That will make my door 22 inches instead of 24, which is what it was. Or, is that a bad idea for any reason?
It’s a personal preference. I tend to think there’s not too big a difference between 22 and 24 inches. And the extra 2x3s will give you a nicer look with the tile. If you’re getting a custom door I’d lean toward the plan you put forth. I used a PVC trim in that tub so that there wouldn’t be any wood rot.