Believe me, I'm the absolute last person to tell someone to "git gud", especially someone who has played "all the souls games". I haven't played any of them, because my frustration tolerance is nowhere near high enough for that. That being said:

Are you staying rested? That doubles your stamina regen. Adding comfort to your base will increase the amount of time you keep the rested buff, to the point that eventually it lasts longer than the sun is up. As a bonus, it also adds 50% health regen, 50% XP gain, and doubles your Eitr regen (assuming you've made it that far).

Additionally, night time makes you cold, which drops your stamina regen by 25%. Being wet reduces it by another 15%... and those effects stack. Running around in the swamp at night is ridiculously bad for stamina regen, especially if you're not rested up.

Increasing your skills reduces the amount of stamina drain for running, blocking, swinging a weapon... by up to 40%. Assuming it's farther apart than the 10 minute "no skill drain" buff lasts after you die, every time you die you lose 5% of your skills... which translates directly to using more stamina to do everything.

You say you're eating good food, so I'll take that at face value... but if you're not rested, you're throwing away half your potential stamina regen. If you're not skilled up, you're throwing away another 40% of stamina regen. If you're cold and wet, that's another 40% cut. If all of those things are true, and you're running through the swamp at night without being rested and with low skills because you're dying all the time... your stamina regen is perhaps 12% of what it could be.

There are more ways to mitigate stamina drain than food, and if you're not using all of them then you're just not trying hard enough... which, as a souls player, I'll assume you already know. This game's description says it's "a brutal exploration and survival game". Take that into account, and use everything at your disposal to increase your chances of survival.