How to prepare for safer sex hookups?

I (31F) have had one partner (31M). He had a full STI test early in our relationship which was clean, and I was on birth control, so I never worried about any “side effects” of our sex. That long term relationship ended \~10 months ago, and I’m feeling ready to date/hook up. I’m excited about having sex, but nervous about the risks, since I never needed to think about safe sex previously.

I’ve:

* gotten the Gardasil 9 series to protect against some HPV strains
* had an IUD for a few months now
* used condoms with my ex, so know how they work

Anything else I can do to keep myself and my partners safe? I’m particularly interested if there are other STI vaccines – I looked a bit but didn’t find anything.