Whoever Allah guides is truly guided.
Guidance is His to give, so ask Him for it
After the story of a learned man who lost his way, the verse says whom Allah guides is the guided one. Ibn Kathir cites the opening words the Prophet ﷺ used, reported by Ibn Mas'ud: whom Allah guides, none can mislead; whom He misguides, none can guide.
You have read the books, watched the lectures, argued the points. Still you know people smarter than you who drifted away. Guidance is not a skill you master. It is a gift you keep asking for, seventeen times a day in al-Fatiha.
If I learn enough, I will stay on the right path.
Guidance is Allah's gift, so I keep asking for it humbly.
In your next prayer, say ihdinas-siratal-mustaqim slowly and mean it as a request.