You don’t have to do anything.
That being said, when used, condoms provide an excellent barrier against HIV, unintended pregnancy, and any STIs that are passed from penis to anus, vagina, or mouth/throat. PrEP only stops one STI incredibly well: HIV.
People who are concerned about other STIs continue to use condoms alongside PrEP. Some people are comfortable with using PrEP to stop HIV and aren’t as concerned about other STIs, since PrEP also includes frequent checks for other sexually transmitted diseases. Others aren't comfortable with this approach and prefer to use a condom along -with- PrEP.
Some infections transmitted by sexual or other intimate contact can also be effectively prevented with vaccines, specifically HPV (genital warts), Hepatitis A, Hepatitis B, and meningitis.
The CDC recommends condoms to prevent the transmission of STIs. You have to make the choice that is right for you.
Reminder: even the most dutiful condom user forgets that STIs are spread through oral/genital contact. Research notes that most people do not use a condom for oral sex. Whether you decide to use PrEP + Check or PrEP + Condom + Check for STI prevention, make certain your "check" includes an oral / throat culture for infections that spread that way, too!