I guess you are probably free to walk into an ocean regardless of vaccination status, I'm not sure what other situation post implementation of the international passport system would reasonably be described by a 'right to exit'.
The point is if another destination would have you, it is a violation of your right to be unable to freely exit. If hypothetically Canada did not allow you to board a non-chartered plane to emigrate I would argue this would be encroaching if not outright violating this right.
I guess you are probably free to walk into an ocean regardless of vaccination status, I'm not sure what other situation post implementation of the international passport system would reasonably be described by a 'right to exit'.