That's the right way. A couple of my clients have pressured me but I said flat out, if you require it I guess I won't be working for you anymore. I could use some vacation time. One figured out pretty quickly and said that I wasn't getting the vaccine regardless of what they said. I know the other might have me stop helping, but will get desperate within a week and have me back. A big part of standing your ground is not showing any give when they press. They don't want to sacrifice much so hope you'll cave when they make an empty threat. If you cave you've lost the bluffing game. If you aren't bluffing and will happily quit, you'll win every bluff. You don't care because you aren't going to compromise. They can do what they want, you just won't be along for the ride.