Ok…so you can’t reconcile with many of the doctrines of the faith.
I’m not surprised at all.
Because if you look at each one of those doctrines by themselves and try to use your reasoning to understand them, it is extremely difficult. If you try to research their veracity in the bible, relying on a prayer to the Holy Spirit to reveal all truths to you, it does not work. This doesn’t mean that these doctrine are untrue. Nor does it undermine the power of the Holy Spirit. This identifies that it was never God’s will that the Holy Spirit would be utilized as a “personal interpreter” for the bible. Anyone who claims it to be so, is fooling themselves, at their own peril. The Holy Spirit guides us into understanding in cooperation with our genuine seeking and prayer…and it’s power is manifested throughout our lives, revealing aspects of the faith to us as God wills it, sometimes through reading the bible, often in other aspects of our lives. But the Holy Spirit is first and foremost unified to Christ’s Church (Catholic Church).
That is why we must trust the Church for all understanding…precisely because the Holy Spirit primarily works through her. Sure, He (the Holy Spirit) works through individuals as well. Not just Catholics. His omnipotence certainly allows work to be done in every realm. But again, His primary channel of work is accomplished in unity with The Church.
Many non-Catholics will feed you lines about the fact that if you just “follow Jesus”, that’s all you need. “Not some church”, they’ll say. The problem with that is that “following Jesus” is not a clear path. Of course, it is the only path. He indeed IS the WAY (and the TRUTH and the LIFE). But the path is illuminated by the permanent, unchanging teachings of Jesus Christ…in more practical terms, by the doctrines of the faith preserved for all time and guarded for all time by the Holy Spirit. Doctrines are the lamp posts which illuminate the narrow path of Christ.
So, why is following Jesus not a clear path without a preserved, consistent, unchanging teaching? The evidence is ALL AROUND YOU. Remind yourself as you look at all the posts on CAF here about private interpretation of the bible, about statements and proclamations regarding faith and morals without any source of authority. That’s the non-Catholic “way”, a sparsely lit source of partial truths, which illuminate the true path only on occasion, and on other occasions will attempt to shine light on alternate paths (no baptism, OSAS, etc.) which lead to nowhere.
All advice you get from non-Catholics about how to follow Jesus is questionable at best, and should be challenged continuously. Why…because a particular one is not true? Perhaps. But more importantly, because (and this is important)…because the body of “truths” from the non-Catholic community is INCONSISTENT, EVER-CHANGING, NON-PERMANENT. Exactly what we DON’T need as Christians to try to illuminate our path.
You can’t find the true path that way because you don’t know who to listen to. Far too many of them disagree. And who are “they” anyway? By what authority do they transmit the truth to you? Think about that the next time you’re listening to someone explain the “truth” to you. By what authority??
To that they’ll say, “The Holy Spirit, guiding me through my bible”.
Doesn’t work that way. See my explanation above. If it worked that way, there’d be NO DISAGREEMENTS. But there are. And sure, not all Catholics agree on EVERYTHING either. Most of us do, but not all. But listen, when it comes to doctrine…to official teachings on faith and morals…to the essential illuminating facts which guide you into all understanding through Christ…faithful Catholics do NOT disagree. That’s because on those matters, The Church DOES NOT WAIVER. Never has…never will. It can’t, you see. Christ promised that the gates of hell would never prevail against Her.
So, as to your OP…“how do non Catholic Christians justify their faith?” If by justify, you mean, to show evidence of unwaivering truths…the answer is “THEY CANNOT…EVER”.
God Bless.