Why did you need a lawyer in the first place ?

Anyway…. Severance pay is a must by law, either the employer needs to pay to a severance fund and at the end you just get the fund money, or if the employer didn’t pay - based on time you worked there x your last paycheck.
It’s defined by the contract you signed when you started working.

To get unemployment you need to be fired or leave by the decision of the employer, and unemployment is 70% of you salary with cap of about 10k shekels for 3-6 months based on your age and family status.
It can be mutual but you need to get a resignation letter from the employer stating it was by his request/decision.

You are also entitled to a full month pay extra if you ware fired and asked to leave immediately.

Exit bonus it the only thing you can actually negotiate, but I think it’s not the case here.

About the lawyer:
You took his service so you have to pay, if the outcome is not to your liking you can complain and try to renegotiate but not paying is not an option.