It is true that we cannot completely evade Fiat entirely, in our quest for bitcoin adoption but it doesn't mean we should keep more of our money in Fiat, besides, most of us earns in Fiats so after using part of the money to invest in bitcoin, the other part should be kept for daily needs and all that but it will be unwise for anyone who owns bitcoins to convert to Fiats except for someone who earns in bitcoin.
We cannot avoid fiat or ignore fiat in any way. Just because you are investing in Bitcoin does not mean that you will use the remaining money for Bitcoin investment after meeting your needs. You also need to use your money to protect your investment and it would be wise to diversify your investments.
When you are using the remaining part for investment after meeting your needs, it means that your savings are only in Bitcoin and this money is necessary for your real life. But as the general rule of investment is, never use your necessary money for investment. Choose such money for investment, if losing the money will not affect your quality of life or you will never need the invested money for any purpose. But as you say, if your investment is lost in any way, your life will change completely.
Even during Bitcoin investment, you need to focus on safety measures. If you want to be successful in long-term planning, you must have more fiat reserved. Because, you have to keep in mind the emergency and keep in mind the purchase of essential items. Suppose you use a part of your income for investment and another part for meeting daily needs. What will you do when suddenly you face a big accident? Will you agree to sell the investment at a loss? Even if you are able to sell it at a profit, you still fail in the investment. You will regret selling this investment. You should even keep another fiat fund that you can use to purchase essential items like a desktop, car or necessary furniture.
For investment to be successful in a long-term plan, you need to have more fiat. You can decide the amount of fiat savings depending on your situation. But I would say, divide your income into at least three parts, from which 1 part is used for meeting daily needs, 2nd part is saved for reserve fund or emergency fund and 3rd part is used for investment. Or you can invest another 4th by dividing it into 4ths and investing in real estate, which will be your alternative source of income and you will be able to use more money to invest in Bitcoin.
So I don't think it's wrong to keep more money in fiat. It may be your personal choice.