Legion
Slightly cynical, mostly okay, completely drunk.
I don't have a clue what the Steam Deck defaults are, but I will say that the game is a LOT easier if you change the default controls if they're like they are on console. They stuck heal on up on the D pad way off where you have to take your hand off the left stick to heal, but then they bound Y to something that you never, ever have to access quickly (change tool), so I'd highly suggest you bind the heal to the easy to access button and the tool switch to the D pad. It's a million times easier to heal in clutch situations if you don't have to take your left hand off the stick to do it!
Other advice for sekiro is to practice parrying, a lot, on the first minibosses (other than the stupid ogre guy who is an infamously bullshit first boss cause the techniques you have to use on him, dodging everything, apply to exactly zero other mobs in the entire game, besides the other identical ogre guy). I got really stressed out my first playthrough and gave up pretty quick (in the flashback segment, before I even got to Lady Butterfly). Then I watched a walkthrough and played along with it and since then I've played it repeatedly and love it. I know a lot of people hate walkthroughs and think it's giving up, but I find with certain kinds of games, especially short replayable ones, that that's a great way to "get into them" instead of just being infuriated you can't figure out where to go or how to beat a boss.
EDIT: I've been playing a TON of easymode cheap-looking open-world Sekiro, aka Rise of the Ronin. This game is incredibly fun. It's like, a dumb ubisoft style collectathon, but somehow all the combat and just the general traversal and stuff (ex the super responsive glider and horse controls that were clearly tuned around fun instead of realism) combine that I actually want to go chase all those icons around the map and clear out all the repetitive bandit camps. The combat is GREAT. I'm playing on normal, and it's really easy compared to previous Team Ninja games like Wo Long or Nioh, and I've heard easy's a big step down in difficulty from that, so it should be a great intro to this kind of game for people. The game can be played either via dodging everything or parrying everything, and the parrying is really fun and rewarding so that's what I do most of the time, but the game's easy enough that you can pretty much facetank everything if you're at a high enough level and just heal all the damage and be fine.
Also the companion system is massively improved from Wo Long, on "missions" you can take along companions, and you can switch to them and play as them instantly. If you get killed and your companions are up, it just switches to them and then you can use them to rez yourself.
This game got really overlooked and trashed on release, I think mainly for the bad graphics and general "AA" feeling of it, but I think they're kind of a strength since it's clear all effort went into just making a really fun open world game with really fun combat. This may be my game of the year even though it has absolutely none of the polish of say, FF7 Rebirth, none of the uniqueness of Dragon's Dogma 2, and way, way lower production values and T&A than Stellar Blade.
Wow thanks for the advice!
The control scheme is a bit clunky, LB and RB the black/attack keys, LT and RT are prosthetic weapon/grapple. I hear you about the DPad-Up having to be the heal but that one doesnt bother me much- Jedi:Fallen Order is the same thing and its muscle memory to me.
About parry practice: you know that guy who cannot die in the temple? I'm just constantly practicing with him. My goal is to get 10 instant-perfect parries in a row. I can do a perfect deflect every 2nd or 3rd block, but it NEEDS to be better.
And yeah it absolutely clicked with me, its fucking painful but as my therapist says: embrace the suck.