Only certain bosses have ever been a 'guaranteed' death for me the first time I encountered them, trash mobs are almost never that dangerous and you can learn their attack patterns without getting hit. I hate to say "git gud" but that's basically what it comes down to. If you can manage to beat the first Dark Souls game, the two sequels are way easier by comparison.
At least with Sekiro you seem to have more mobility, and thus more options including running from tough enemies until you can get stronger or find something they're weak against.
I have zero issues with the 'git gud' mentality, as i have been 'gitting gud' since the first day i played video games and to date, there is no video game i did not manage to finish, no matter how hard (with a couple of notable generalised exceptions such as bloody battletoads for example). I actually enjoy a hard game and i put many of my games on hard. My problem with the souls and the rest of their games, is that the difficulty is not because the game is difficult, but based on the ridiculous control scheme (according to me of course) where if i pressed a button to roll while in the middle of the attack, it will execute these in order, without cancelling if i hit another button before the attack is in motion. Meaning, SLOW. I cannot understand the mentality of this, all other action games happily respond as soon as you press buttons and 'cancel' previous commands that have not started.
People say this adds realism to the game and a sense of 'owning' your choice rather than button mashing, but in my opinion this leads to excessive grinding, not for grinding's sake at all, but to learn each and every enemies attack/defence patterns. At the end of the game, it feels less than playing a game, than writing an encyclopedia on the patterns. Don't get me wrong, i enjoyed DS3 as far as i played it, but i quit after realising this pattern. I simply cannot afford so many hours in learning a game so well. DS with say God of war controls would be a game 1/10 of the length and simply because of 'better' controls, not down to difficulty. If somebody ever patches the games to respond like i expect (like most) then i will happily play them as i like the lores, the graphics and everything else. Just hate this slow-as-mud 'haha - you chose to roll or attack - no turning back lolz' mentality. Feels like i am playing an FMV game.