it would depend on luck for the first few days - I’ve got weapons and I know the fastest way to gtfo of the city so I can rendezvous with my family - they’ve got some arable property in an easily defendable, low population area. family isnt prepper level but they’re big into organic gardening/natural remedies - in the late spring through late autumn they dont need to buy groceries, the land provides… there’s plenty of water there in the area, and building a water wheel isnt that difficult, nor is wire wrapping (just tedious) so as soon as we survive the winter of year 0 (and winters are pretty mild) designing a grain mill (flour) and basic electrical generation (parts are just laying around) would just be a matter of a few months. my father is big into black powder tech - i grew up learning how to manufacture it, how to cast lead shot, how to care for rifles. 1700s level tech is very simple (not super accurate but it’s better than limited modern day rounds).
so, end of post apocalypse, year 1: permanent food and water supplies secured. electrical generation secured, electrical grid expanding. base acquired & outfitted. protection/weaponry secured.
years 2 - 45 (probably got another 45 years in me), hard but rewarding survival as I rebuild society. pass the reins onto my very large family. world domination in 250 years.