Heirloom vegetables grow more slowly and spoil much more quickly than modern crops. This is because modern crops have less nutritional value - https://jeroenvanbaar.substack.com/p/data-dispatch-4-the-falling-nutritional
That article recommends eating a better diet. Sure. Seems a bit idealist. Here's some more actionable advice: everyone should take a multivitamin and magnesium glycinate. If you live somewhere that gets a winter take vitamin D too.
I'm speaking from experience here, I used to get sick every winter and my skin would get so dry it would crack and bleed. Take your vitamins.
I fuckin love canned tuna (skipjack or light, not albacore so much).
I've only tried a canned fish besides tuna or salmon once, it was sardines and I didn't like it. I'd kind of like to try other canned fish but I'm afraid I'll be disappointed again.
You could try a medium-sized fish, like herring. It's often canned in some kind of tomato-sauce and it generally breaks up more due to the size of it. No skin or bones. If you like tuna, this could be right up your alley.
Generally, I'd also advise to have some good bread with it or some crackers or something like that. You could also try it with rice, I think.