Here. If you scroll down, you’ll see that the Red Cross is not taking convalescent plasma donations from anyone, vaccinated or unvaccinated, because there’s no hospital demand. The stuff generally didn’t work.
https://www.redcrossblood.org/donate-blood/dlp/coronavirus—covid-19—and-blood-donation.html
You’ll also see that the Red Cross is taking blood from people who’ve been vaccinated with vaccines developed in the free world including the U.S.A.
OK, but I’m not getting calls to donate plasma