I believe those statistics are based on trans women who a) are in sex work and b) engage in anal sex regularly. (No judgment from me on either front; I believe people are entitled to do what they need to do to be happy and/or survive.) I would expect that the transmission rate of HIV for a post-op trans woman with a limited number of partners would be roughly similar to that of a cis woman in the same situation, which is to say, not high unless you skip the condoms regularly with partners who haven't been tested. I can't give medical advice, but I'd definitely research thoroughly before committing to the prophylactic drugs; I know people who've taken them and it's a pretty miserable experience.
Step 1 is to get *yourself* tested. People with penises can contract HPV - in fact, they're the vector by which people with vaginas usually catch it - so a pre-op trans woman can't assume she doesn't have it. Odds are your tests will come back clean, but it's good to know your starting point.
Step 2 is the obvious, to follow all safe-sex recommendations for cis women. Always use a condom, and always assume you can catch something unless you've seen recent test results on your partner. Don't double up on condoms, make sure you use condom-safe lube (and lots of it, to prevent micro-tears), don't have unprotected oral or anal sex, oh, and remember to pee before and after sex to prevent UTIs.