I have so much worthless fiat in my bank account, but Bitcoin seems too expensive to buy now. What a dilemma.
Sounds as if you are gambling too much and waiting too much.
You should create a plan in order how to invest that fiat and at what price points.
Let's say for example, you have an investment fund that includes the fiat in your bank that is about 50% bitcoin and about 50% fiat.... and maybe your dollar amount is $10k (just using a round number). Then, for example, you might allocate $2,500 to invest right away, and $2,500 to use for dollar cost averaging purposes - meaning to invest about $475 per month for the next 6 months, and then the remaining $5k would be held to attempt to time and to buy on a price drop.
I just gave one example... there are a lot of ways to devise a comfortable plan that makes you feel as if you have sufficient stake in the game and that you are not too much allocated in fiat.