People have done Aveiros after the greatest revalations. People witnessed real Nevua and yet mocked it. Don’t worry about your Bechira.
It is not your job to make yourself Nisyonos. Hashem made the Yetzer Hara, your job is to fight it. Remember what happened to David Hamelech when he asked for a Nesayon.
By Avraham Avinu it says Vehe’emin Bashem Vayachshive’ha Lo Tzedaka, although he just heard the Havtacha from Hashem. Emuna is a Midda that doesn’t depend on blindness. It has to do with steadfastness. Surely you should have Emuna with or without any proofs, but why shouldn’t you build on it? Emuna is the unmoving loyalty and bond. That comes after knowledge. It is partly based on what you know but is mainly a Midda.
I’m not advocating pilosophical discussion or even scientific, necessarily. Build on your Emuna with stories or with Torah or once in a while some proofs that are out there.
The point of your second paragraph still evades me.