I appreciate everyone’s input. I know next to nothing about transition pieces and custom making anything. Ideally the side piece of trim of the threshold that I pictured up top would look more like a reducer, angle down toward the floor I'm installing, as opposed to just standing up totally flat. Even if I do the screen mold as suggested, there would be about a 1/4" difference in the transition to the new floor. I attached a photo of what I had in mind, just by taking that piece off and angling it down. This may be out of my level of ability to have it like I have in mind. I may just go with whatever is most simple for me. I just didn’t know if I could buy a piece with this sort of profile already, to make it look like this.