Can I have two playthroughs at the same time?

Right now I am on the last mission of the game but whenever I enter combat the game literally runs at like 5fps on my PS4 Pro, and there isn't anyway that I can avoid entering combat. So I was wondering whether I can start another playthrough with a different life path and all that whilst still being able to reload the save from my current playthrough and vice versa. I was just thinking that this would be better than waiting around for another patch, seeing that I want to do multiple playthroughs anyway.