If you’re watching the OT and you see Hayden that’s your own fault.
Bad memories will pop up subconsciously and there is no choice about that. While one can choose to not accept the content of those memories, they will pop up either way (provided one has normally functioning brain) and pollute the current experience.
Despite having grown up with the PT I can easily watch the OT without thinking of Hayden Christensen whenever I see Vader. As a kid I did imagine Hayden under the mask, but as I grew out of the PT I gradually learned to not think like that. Now I actually find that whole concept somewhat absurd and I can’t really imagine anyone else but Sebastian Shaw. If you’re willing to simply ignore the PT and just focus on the old it really shouldn’t be that hard.