I had moderate mysophobia as a child to young adult. I wouldn't share food or drinks due to a fear of mouth bacteria (and would throw it away if someone else helped themselves to it), I'd excessively clean dishes and cooking surfaces, wash my hands multiple times if I touched something I considered contaminated, cooked meat until it was beyond well done, etc.
It got way better after I went to college for microbiology. Actually understanding microbes helped immensely. I'm still a little weird about other people's bodily fluids, especially saliva, but otherwise probably care less than many people about "germs". I uphold much higher standards for other people's food, but I'll (conditionally) eat food I dropped on the floor, cook my chicken to a bit less than 74°C and eat blue rare steak, ferment my own foods and brew my own alcohol, pull mold off my bread or cheese and eat the rest, and I now wash my hands an appropriate amount.
I can't say no fucks given, but instead a situationally appropriate amount of fucks given, with a lot of extra leeway due to uncommonly advanced knowledge.