The biggest problem with “herbal” remedies is that in spite of sometimes clear POSSIBILITIES of certain beneficial properties (actually from certain chemicals found in the herb), there are no clinically derived and authoritative scientific standards on quality, application, dosage, interactions, side effects and other important matters. It’s a crap shoot and part of why, to a higher degree than “prescription” drugs, the reported results are inconsistent and hit or miss.
I have used ginger with a sore throat - sucking on a small piece of ginger or making a ginger tea with lemon. I would not make any claim it “cures” a sore throat. I think it most likely makes the throat “feel” better while my body’s natural defenses get the real healing done. Of course that is not the same as a “strep” throat which involves a more serious streptococcus infection. Any sore throat with fever lasting 48 hours deserves a test for streptococcus infection which needs an antibiotic.