I propose to expand the topic a bit, and voice other scenarios in which cryptocurrencies will be unavailable to us for a certain significant period of time
what do you mean by unavailable? do you mean that the government banned and blocked anything that could allow us to use crypto or did it simply cease to exist?
not all cryptocurrencies will be permanent especially that they function over the concept of supply and demand which is very unstable at some point a lot of cryptocurrencies would not be the top cryptocurrency like how we see them now
but if you meant that it just simply is not available for quite some time like a day or so then i do not think anything bad will happen to me provided that my funds are as safe as i last saw them
1. We're not talking about “shitcoins”

2. We are talking about bitcoin, ether and other DECENTRALIZED cryptocurrencies.
3. Stablecoins do not belong to them - they are centralized and in fact are not cryptocurrencies in the full sense.
The reasons for inaccessibility may be different:
- legal regulations prohibiting the circulation of cryptocurrencies
- technological problems (e.g. destruction and fragmentation of the Internet, hacking of underlying crypto algorithms, ....).
- global cataclysms (natural disasters, global warfare,...)