I’m saying it’s fine to put some of tools of balancing that in the hands of player. People are different, and especially in games that are dependent on reaction times and hand-eye coordination, have different physical capabilities, so they’re going to experience different levels of frustration by the same content.
I’m also an old fogey who thinks it’s weird for people to need a meta-game structure like achievements to engage with a game’s difficulty settings. You’re here to experience that enjoyable frustration. Why wouldn’t you try to play with your game and find where it’s most enjoyable?
(Granted, it’s not as easy if you can’t adjust the difficulty on the fly. Having to start over to change difficulty is rubbish, unless that’s a thing you’re going to do a lot of anyway.)