Sure, anything might work, but that doesn’t necessarily mean it should be put to chance. While this is a large aquarium, unless it is heavily planted with obstructed lines of sight, the fish would likely still get to each other. Even with plants, though, you may find that the presence of the other fish will stress both betta fish which, apart from being bad for the fish, is also not good for the water quality. Personally, I wouldn’t do it. I also wouldn’t put the fancier fin types in a tank that size regardless of other tank mates. Bettas with heavy fins would possibly not do too well in a tank that size, depending on the filter and a few other factors. A shorter-finned variety would probably do well (something like a plakat, maybe).