I grew up in the Christian church. I even went to Bible college and graduated.
There’s plenty of internal inconsistencies in the Bible that people point to. Honestly, while I was always intrigued by those, I didn’t (and still don’t) think those are deal breakers. What did it for me was twofold.
First, the people and their inconsistencies in belief/behavior. There’s plenty of beliefs, practices, and policies that you can argue, but being kind and compassionate are pretty clear callings without room for debate. The most hateful, spiteful, discriminatory people I know can all be found in a church on Sunday, or at least claiming to be Christian. Not to say that all Christians are like this - some of the kindest people I know are Christians. But as a group, they are appalling.
Second is results. I’ve prayed for plenty of stupid stuff I’m sure. If a god is real, I don’t hold it against them for ignoring my dumb asks. But when I look at the serious stuff - prayers for lost people to come home, for severe illness to be healed, for provision for the impoverished, I can’t see any difference at a macro level between praying and not praying.
I questioned what good religion was if it didn’t seem to improve people or the world, and came to the conclusion that it was a wash, so I quietly walked away nearly a decade ago.
It honestly kinda sucks. It was a huge portion of my life. Most of my friends are people I met through church and college. My family is still heavily religious. I met my spouse through church, and they are not in the same position as me. Barring 2 friends, I have never told anyone I know that I’ve even questioned. Even as I’ve moved through jobs, there’s always been someone who already knew me, so the expectations that come with a religious history and degree have always preceded me. I’m effectively in the closet. Anyone who says leaving is the easy route is ignorant and wrong. It’s hard.