Easy. Disclose the preference of the terms you got from investors to your early employees.
This problem is self created. If you don't tell them the terms of your deal, they rightfully assume the terms will screw them, since otherwise why wouldn't you be transparent? Good workers rationally and rightfully go to FAANG instead of a startup if it doesn't feel like the startup is being fair.
Honestly, startups should be more transparent, because they can't compete on money. If they can't even offer trust and upside, they are offering literally nothing over an established public company.