I have only experienced downsides in being salaried/exempt and would much rather be hourly. Most of the companies I have worked for as a salaried person have been flexible only in the company's favor. Employees are expected to use PTO for appointments but don't get anything extra for working outside of regular hours.

They can't just take away your overtime unless you qualify as an exempt employee. There are federal and state regulations on exempt status and it's worth looking into them or giving the state department of labor a call to make sure your company is allowed to do this. This page looks like it has a lot of detail: Exempt vs. Non-Exempt Employees: Guide to California Law (2019)