Runbacks are a lame attempt at artificially increasing difficulty. I'll happily die on that hill. I love difficult games, but there is a fine line between frustration and difficult.

Elden Ring (at least all the bits I played through) and Sekiro absolutely nailed it. None of the run backs were particularly egregious, and it let me really focus on experimenting and learning to feel out the difficult fights. Celeste is another good example. I have dropped hours on some of the later levels trying to master them, but never once got frustrated.

Hollow Knight I never finished because I got stuck on a boss and the runback was just way too long and annoying. I loved everything else about the game and want to finish it eventually.

Edit: I think they have their place as "mods" that you could enable to increase difficulty, and i'd actually probably enjoy it that way. Just designing the game around them is where i draw the line.