I really don't see this as a major risk because the Nigerian naira has been a mess over the years just as you have pointed out, but in other to be able to buy Bitcoin, you need to change the naira to dollar, just that the purchasing power will reduce compared to before, because before we used to buy one day with six hundred naira, but currently speaking it's now #1548, the biggest benefactor of this spike in price is those people that has been holding the us dollar for sometime now before the spike are the biggest winner because their purchasing power are still intact.
So I think that paying attention to how low a country currency is, is just a baseless excuse not to invest in Bitcoin.
You speak like a good investor because if we are to go by what OP is saying then we all need to wait till the currency has returned back to the original state it was before we can start buying Bitcoin with our currency. Such a baseless excuse as you said

Let me make it very simple for you to understand. I am not saying that you should not invest but make your alternative calculation before investing. You can invest at all time. And the risk is always on you not another person. And if you don't know you have to know now. The fluctuation of US dollar affect bitcoin investment most a country like mine and those countries that have the same fate with mine. Right now $1 is N 1,548 and the price of bitcoin is $94,750. And my interest is not even bitcoin but $/local currencies. If you invest now and you invest with $2,000 now and in 20 years to come bitcoin hit $700,000+ in my country $1/N100. Do I gain or do I lose? This my point please understand before commenting. You are free to invest at all time and wait to 100 years to come.