3 was the best. 4 was ok but starting to decline. You could tell because the dragon combat system had literally no thought put into it. 5 was just plain bizarre and I’ve never played 6 because it was never released in the U.S., is now defunct and was a POS P2W (probably) Chinese mobile trash game.
However if you haven’t heard there is a “spiritual successor” to the BoF series: Tears of Magic
It really feels like we’ll be playing another BoF 3 soon. Hopefully Crapcom doesn’t cease and desist the project as these once glorious game publishers love to do.