Since you say 200+ without upper limit, I will say Yes if the tank is big enough (I cannot provide a number unfortunately) to allow for a different, defendable territory for each betta. And like you say a lot of places to hide or swim away. Every betta has a different personality. Some of them might insist on killing the other one unfortunately.
It also matters which fish is introduced first. If a fish already decided that the whole aquarium is his, the new one has more chance to be bullied. Likely a newly-arrived betta might be more timid with fishes that are already at-home. It might be better to introduce both at the same time, with the lights closed. Don't leave the lights open for too long, you will reduce aggressivity like this.