your bitcoin would be inaccesible since bitcoin requires internet and a mobile phone. You could no longer exchange it for goods and services or physical currencies. The only thing you can do is to move out to another country where there is no conflict in order for you to survive, or just seek some help.
It surely requires internet but you can use any device not only a mobile phone as long as they support internet and they have a browser in them. Why would you move to another country when you can just wait for the war to end because they are going to restore the internet after that.
Traveling to another country can be a hustle and can cost you more but it can be worth it if you have relatives there and if you are going to do other business and not only by finding an internet connection only to access your coins. I heard on the news that Elon Musk has provided starlink to the Ukrainians for them to connect to the internet. that should keep them going.