Hayden’s voice could probably be fixed - it would just take quite a bit of effort.
We’d need to rip the center channel of when he’s speaking from other parts of the film and isolate his voice with AI. Then we use that as source material for a voice clone. And then we input his lines from the Kenobi scene into the new ElevenLab’s feature. His lines would then sound like his younger self and be delivered exactly how they were originally.
But yeah that’s a lot of effort for only one piece to the puzzle. The camera work is always going to be out of place.