I suggest you’re not thinking correctly about the problem.
If you’re going to be stranded temporarily someplace but rescue and civilization will return, then a “survival kit” is a useful concept.
If those things are gone forever, then what you need are SKILLS, not stuff.
You will have to feed & care for yourself every day for the next 50 years. No, you can’t plan on just stocking up on 50 years of canned beans, penicillin, and reading materials.
Stocks of canned food might last a couple years. Sophisticated medicines might last a couple years as well, but without the knowledge of diagnosis, you’re as likely to hurt yourself as help.
To survive the magical destruction of civilization and humanity, you need to have the skills of an Old West mountain man or medieval peasant. If you can farm with a sharp stick for a plough you’ll have a chance. If you can make fire from two sticks you might last through the first cold winter.
Very few humans were ever able to survive solo. It takes a group to live the natural way. You need to eat every day, but you also need to make some tools (spears, traps, ploughs, domesticated animals) to be able to eat every day.
We have had discussions here about this before, and many people pointed out that an intact but depopulated city contains a tremendous wealth of stuff for you to use. The trick is to live off that at first while learning how to become self sufficient against Nature before the civilized stuff rusts, rots or is eaten by vermin.
If the cities / towns are largely destroyed that means you’re forced to revert to Nature much sooner. Hope you’re a quick learner & in good physical condition.
If there are many survivors, even 1% of the current population, then you can assume most of them will be killed fighting with each other over the remaining local remnants of civilization. And a solo person is not able to defend their possessions against a group. Rambo movies notwithstanding, 5 low-quality attackers can defeat 1 superb defender every time.
In my opinion, the best preparation for post-apocalypse survival is to move now to a largely uninhabited area with decent climate and learn to subsistence farm. With a few years practice backed up by civilization, you’re well-positioned to make the transition when the Big One hits. You’ll live to the ripe old age of 60-something assuming you have enough kids before then to take over the hard work as you get to be 55+.
Not willing to go that far? Then plan to perish like the rest of us.
Certainly as a suburbanite you can stock up on canned goods and practice your camping skills & shooting. That’ll keep you going for 6 months or so unless you get ambushed by your former neighbors. (That’s my plan.)
You can move now to a rural / farmland area and grow your own veggies & hunt occasionally. Those skills will keep you going for a couple of years.
But those are both plans to fail. “Survival” in this context means staying healthy in primitive conditions until dying of old age in those same primitive conditions, not staying just barely alive only until rescue comes to take you to an ICU. Very different problem. Very different solution needed.