Hi Hugo! You are asking why you're still single; let me offer you my two cents.
You want to meet a girl who is 20-30 years junior to you; you want her beauty, her youth, her innocence, and her zest for life. You say that you can offer "dedication, attention, patience, protection, support, encouragement, challenge, loyalty, respect, love, etc." Sorry to disappoint you, but to me, it sounds more like a good father rather than a romantic partner. Most likely such a girl already has one dad. Why would she need another one?
A young girl who is active, open-minded, hungry to learn and explore, doesn't need someone to protect her from life experiences. She wants such experiences, she needs a partner to grow together.
Furthermore, in just ten years your sex drive will inevitably decline due to natural reasons, while she just reaches her prime. In 20 years, you might, god forbid, begin to face serious health issues. At that time, she will be at her career peak. Do you believe your young wife will be looking forward to becoming a caregiver for her aging husband?
Of course, you are entitled to your own opinion and free to look for whoever and whatever you want. Just be prepared, in case you find such wonderful 18 y.o. princess, to be left behind for someone who may offer more than you.
Slavic women are often accused of having unrealistic expectations in a marriage with foreigners. I see that some foreign men still believe in fairy tales, too.

Respectfully.