Dark souls saves very often. you can't really save scum. if you die, you die. if you fall from a cliff and you quit out before the "you died" shows, you are on the last stable ground and alive. if you quit out during a boss battle you will load in before the boss fog but if you used estus or items they will not be restored. enemies will reset their position if you load in but stay dead if you already killed them. this is true for every platform and every soulslike game made by from soft . if your game crashes you will load in a few seconds before the crash.

but you also cannot really pause the game. your only reliable glitchless way of "pausing" is quitting out

You can save whenever in DSR, but you can't e.g. reload a save before you died because you autosave when you die and you only have one save slot per run.

Also, though I love DSR, I've got to say it's kind of tedious to jump into for a few minutes as it's a bit slow to get into with the loading, dialogs and stuff on startup

I've tried both. CEMU works better for me out of the box, but I did absolutely no tweaking. I also run my SteamDeck 100% stock, so I can't speak to anything than a literal "out of the box" experience for both. I'll say, terrible battery life with CEMU and Breath of the Wild. 2-2.5 hours from 100% to dead.

with the latest updates and after an initial shader caching the game runs smooth as butter(capped it to 40fps for battery reasons)