COVID binds through eyes. When you are staying in closed room with enough viral load, masks on people are useless (well, they provide some psychological comfort probably). Sorry to say that. You might wanted to use full face respirator or tight goggles with mask in closed room to avoid virus to bind through air. Mask on barber won't make a big difference.

BTW, I have seen vaccinated catching virus, unvaccinated, with masks and without masks, people staying in isolation at home, people that were going out actively... all got virus :-) all got it multiple times... including myself, recent strain caught a few months ago in Quebec City, Canada. Ironically first one in 2020 caught in Toronto, Canada as well.