Nobody’s giving or getting head with a condom. People who stay on top of preventative measures tend to not bother with condoms since PrEP became prevalent, because the rest of them you can get with or without a condom due to oral.
Preventative:
1. Gardasil 9 (vaccine against 9 strains of HPV, prevents genital warts and cancers caused by HPV)
2. Monkeypox vaccine
3. Meningitis ACYW vax
4. Meningitis B vax (35% effective against gonorrhea)
5. doxyPEP (two pills of doxycycline taken after sex, 90% effective against syphilis, 80% chlamydia, 50% gonorrhea)
6. PrEP (prevents HIV infections)
7. and the usual suite of vaccines against the rest like hepatitis A/B, mumps etc
You’ll notice all of these give you far more protection than a condom would. Again, especially since oral is a thing.
Treatment of the bacterial ones (which transmit through oral too):
1. syphilis - butt shot of penicillin
2. chlamydia - 1/2 pills of an antibiotic
3. gonorrhea - a week of doxycycline pills or one butt shot of ceftriaxone
Remaining unpreventable/untreatable one is HSV. Half of the population has it. Condoms dont prevent it either.
Hepatitis requires blood contact and as such is not necessarily considered an STI, but hepatitis c is curable these days thanks to DAAs taken over the course of 8-12 weeks, and a/b variants have vaccines.