Divorce entitles you to immediate liquidity on illiquid assets? That’s crazy. I’d understand 50% on vesting. Unicorn employees tend to have more than twice as much illiquid stock as they have cash.
If you have RSUs, you get to go through the fun process of either giving some value to these RSUs and paying off the other party's community interest in that valuation, or you can try to argue that RSUs have a zero dollars value until granted. Good luck with RSUs and stock options either way, as it can become a complicated mess of laws and formulas.
You can try to do the same thing with stocks, where you pay when you vest or sell, or sell on behalf of the other party, but in my case, and I suspect many others, I wanted the cleanest break possible and I settled on a payout amount simply to reduce the amount of communication with my ex-wife that would be necessary to pull this off.