💃🏽How do you calculate before?

I want and maybe even need to ask my boss for a raise.
On the other hand, there is a high probability that he will refuse and even be fired.
It is better to stay with what is given today than with nothing.
It's better to ask for a raise and get by in life than to take the risk and stay with the low salary.

What should be done?
It should be noted that this is a rare job (doing almost nothing, and bringing home a reasonable salary) and it would be very difficult for me to find something else under these conditions.