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’ve been playing flex for so long that I can play multiple hero, while I agree you should push yourself and learn how to play against your counters, if they are full countering you then there’s only so little you can do at that point where it just makes sense to switch to get any sort of value