As long as we are not talking WW3,
Russia is hands down best place to be, it could easily stay cohesive with a lower standard of living, has been switching to internal supply chains for a decade now, has swaths of empty land and population not foreign to a concept of living off land, but most importantly it is under populated.
Low population density - check
Good defense - check
Cultural and societal background necessary for a post collapse - check
Carrying capacity of land - check
Energy (oil/atomic) - check
Nukes - check
Base of LOWER(more resilient to supply chain disruptions) tech industry - check
Amateur astronomy, specifically astrophotography. Tons of fun, takes patience and focus as well as tons of time outside, strong community and a sense of purpose, since you can actually realistically see stuff no-one ever saw before!
Low population density - check
Good defense - check
Cultural and societal background necessary for a post collapse - check
Carrying capacity of land - check
Energy (oil/atomic) - check
Nukes - check
Base of LOWER(more resilient to supply chain disruptions) tech industry - check
Benefits from climate change - check