I am ballmain in masters and only swap very rarely, even if I have a lot of counters. Many teammates always tell me to swap. Personally, I want to learn to play with ball, no matter what the enemies counterpick, because I think individual skill is more important than always being flexible and counterpicking.
I think the best balanced take is to learn 3 heroes well that can fit in most brawl/dive/poke comps. One tricking will probably get you further, as you’ll learn every situation for that character and naturally become very fluent with them. Like others have said though, if you’re equally as good at wrecking ball as your are sigma, but one fits the team comp better or can counter the other team harder, then that hero has a natural edge to them if all else is equal.