And to make it concrete: where I live we're into emergency (as in, stretching the system past its limits) ICU capacity and elective procedures (which, please note, does not mean optional) have been cancelled or delayed en masse for a couple months now as we've been going through our 4th and 5th waves.
People are absolutely regularly having diminished quality of health care due to unvaccinated people catching, as well as spreading, covid.
Severe outcomes stretch the system more, and unvaccinated people have more severe outcomes.
At any rate, if those nurses weren't vaccinated it's likely more than 30% would be out and a significant portion of them would be dead, so if you want to go down the "vaccines make people sick/more likely to be sick" path then you've just fallen off the rails. The path you have in mind would be a mass death event our medical systems are completely unequipped to handle.
https://www.latimes.com/california/story/2022-01-20/hospital...