Technology

That's not what I meant. I meant that the core experience will be good if it replicates what the Souls games do, which is why they're successful. Many "Souls-likes" replicate the combat, and it sucks. Honestly, the DS1 and Demons Souls combat is pretty rough, but they revolutionized gaming, and the boss fights weren't the unique thing they were doing. Boss fights like them have existed forever.

If you look at the older FromSoftware catalogue, you can see what makes their games special. The older games have incredibly clunky combat, but they still have the core exploration loop. There's a hand built world with care and thought put into every detail, and the game gives obstacles that get easier if you engage with the world and explore. This is often with items or levels, but it's sometimes just with information. This is what makes a Souls-likes, and the copycats that fail are missing this (or they just didn't make an interesting world to explore). Hollow Knight isn't great because of the combat. The combat is fine, but it's the interesting world that's begging for you to engage with it that makes it compelling. That's the core of Souls-likes.