Thank you. That's a very clear answer and much appreciated.
Welcome to the forum.
The answer to the opening question is obvious and you have stated it well in the next paragraph. Condoms are highly protective. The depth of penetration probably isn't relevant. However, as you seem to know, skin-skin contact above the condom carries small risk of STDs transmitted by such exposure, such as herpes, syphilis, and HPV. But sexual position probably makes no difference. Saliva contact with skin doesn't transmit STDs.
For vaginal sex, I suggest you just assume there will be skin-to-skin contact, even if condoms are used. A decision to have casual vaginal or anal sex with unknown or risky partners means the person is accepting the small risk of HSV, HPV, and syphilis. Oral sex is basically very low risk even without a condom, but is probably 100% safe with one.
The bottom line is this: If you demand no risk at all of any STD -- which seems to be your goal for "ultra safe" sex -- then you are stuck with not having sex at all, or limiting yourself to mutual masturbation. And even that may not be truluy 100% risk free, especially in regard to HPV.
Regards-- HHH, MD