For my views on difficulty, I'll use Fire Emblem as an example.
I'm of the opinion that permadeath is a fundamental aspect of Fire Emblem, and a big part of its appeal. It makes the player think strategically, lest they lose not just a unit, but a character that they've come to know. Someone with a name, a story. And then you, as the player, need to make a choice. Do you accept the loss and move on, or do you reset and lose your current progress, but keep the character alive?
New Mystery of the Emblem introduced Casual Mode, which is a nice thing to have for accessibility purposes. It was kept in Awakening for a reason. It acts as a set of "training wheels," of sorts, so that if ever the player wants to try out Classic Mode, it's less daunting. It lowers the entry bar. The knocked out unit is just out of commission for the rest of the chapter.
Fates, however, took this a step further and added Phoenix Mode in addition to Classic and Casual. Phoenix Mode revives any lost character on the very next turn, not at the chapter's end. This basically renders the game unloseable unless you somehow get your entire army wiped out in a single turn, or if Corrin dies. That's not accessibility, but instead removing any sort of challenge whatsoever. In Casual Mode you still have to think tactically, but not so much in Phoenix.
Phoenix Mode was taken out come Shadows of Valentia, and instead we got Mila's Turnwheel, a great quality of life feature. If you just made one dumb mistake or got hit by an unlucky crit, you can back up a few turns and rethink things. It's basically like a save state option built in, but it also has limited uses, especially early on. A fair compromise of convenience vs difficulty.