I think the probably biggest mistake from other studios that try to replicate FromSoft's success is to try to make the games as difficult and punishing as possible.

That really isn't the point. The secret sauce is arguably that FromSoft makes puzzle games disguised as action games. Everything is a mystery, from the lore to the game play. They are rewarding to play because it is rewarding to solve puzzles.

The "difficulty" stems from the game developers anticipating how you will approach situations based on earlier situations, and adding new caveats to the rules. If you don't understand that dialogue between player and game designer, it may appear like it's just really punishing. It's really not, it's always easy if you know what to do. The difficulty comes from constantly being forced to adapt your approach.

It's pretty brilliant how they consistently re-use enemy archetypes between the games. A rat is a rat and a dog is a dog, in Dark Souls and in Elden Ring. They form archetypes, elements of design language. You need that to have that sort of predictability on your easel to be able to pull off the sort of unpredictability they do.