I’m like you in that I can’t stand the grimace and slog model of “perseverance” (and the way some people elevate “mortification of the flesh” as a virtue makes me flinch in horror), unlike in that every time I’ve hit even a medium-hard problem I’ve tended to bounce off and re-script on the assumption I can’t.
So the “aha” was the idea that pushing into a problem can convert a sheer cliff into a hill climb, but that the danger comes each time something looks like another cliff. The proper response is not to bounce but to push. There is no cliff until you can prove it (and don’t trust a facile proof).
Also, now I get to look back at my many “I can’t”s and re-examine them for opportunities to push.