If we have a collapse there could be a civil war of sorts so wouldn't be long before the power grid goes offline, then BTC will be useless almost instantly. Bullets and canned food will have far more value.
It's happened it a few places in the third world but not on the scale it will be if it happens in the US. People aren't as docile today as they were back in the 30's when the great depression hit. they aren't just going to say "aw shucks" and retire to their shanties and eat hoover stew. people today are pissed off and armed to the teeth.
In this case, are you expecting BTC will 40x nominally, or in real terms? If it goes 40x because the dollar loses all value then you’ll still have lost value in real terms.