I would go on a journey with them. Begin to build a foundation with them of who God is. Who created us. Start with a foundation with God (not a God of the Bible, but just our Creator and provider who we can see throughout creation (outside of the Bible), our creator. What is our purpose in life, why do we do everything we do? We do everything to glorify Him. The first greatest command is to love you God with all your heart (your want or your will), your mind (your knowledge of Him), and your soul (your actions). Loving your neighbor as yourself is a function of loving God, it is how you love Him with your soul. Jesus left heaven to come to earth as a human to show us how it should have been done, to fulfill God’s covenant with Abraham, and to become the high priest for us, so that we can come to know God again as it was intended.
Build this relationship with them, to where you both agree on the main foundation things. Then when you bring up creation, they won’t see you as a heretic, they will know your foundation. They still might not agree with you, it might open their mind a bit. Then you can try to explain evolutionary creationism, not evolutionism to them, which is probably what they know, or think they know. They might not know very much about actual evolution. But if they are scientific and logical minded, and start to see how it is still to argue science, they are hopefully not shaken as you were, because their foundation is in God, the creator and provider of us all, who cannot be moved and will never change, and it always good, just, merciful, and loving. Then a small thing like the possibility of evolution might not shake their foundation or faith as much.
Though I firmly believe that those who seek Him, will find Him. It sounds like you were seeking Him, and even though you had troubles, He found you and brought you back. Make sure they are seeking to know God, the God who created us and wants to have a relationship with us, not a God of the Bible.
Now to clarify, I do believe these are the same, but if you approach it as (our Creator, not a God in the Bible), then their pre-concieved God of the Bible logic won’t be there to alter the truth. Don’t seek to confirm your current thoughts (even if most of it is Biblically based), seek to know Him, and ask Him to reveal Himself to you. God is real, He is outside the Bible, we can see His love through people, His majesty through creation and evolution. Anyone who is an engineer should be marveled and dumbfounded when they learn how incredible of a feat evolution would be to design. And the logic of how God works throughout the Bible in slow strange processes to accomplish His will. There are very very few, if any massive, strong, instant changed, like a YEC surmises. It is about slow, strange processes, seeds, small things that grow to large things that bear fruit. Humans, from a sperm to a baby, to a child to an adult. Organisms to a money to a human. Israelite’s seed came from Abraham, who was later planted in the promised land, had many branches cut off until Jesus was the ultimate fruition of that promise, the mustard seed that planted the kingdom of heaven.
But hopefully, knowledge or belief of YEC shouldn’t change one’s faith a single bit. What is their faith in? The God who created everything in this universe? Or their interpretation of some writings?
The Bible is just ONE way for God to speak truths to us and reveal things to us, it is A tool(not the only way). Jesus (not the Bible) is the only way, and Jesus is a manifestation or fulfillment of the true image of God which all leads to God, our Creator. If you want to know God, read the gospels, not Genesis, see how Jesus lived, the only non-flawed human image of God. There are many tools our there how God reveals Himself to us. That is like seeing a cruel mass shooting, and that shaking your faith. Our faith shouldn’t be in man, or their actions, nor in a book (even if God’s very words are in that book), it should be in God. The fact of evolution or not, even if YEC’s are right, should not change one’s faith a single iota. I don’t buy into the argument that 'if this is incorrect, the whole Bible can’t be trusted". God can always be trusted when He speaks to us and gives us peace. The Bible is just one of the many ways God speaks to us and gives us unexplainable peace.
If Adam never existed, nor Noah, and they were all merely stories. That doesn’t change the way I live. I live to glorify my Creator, and I am thankful He loves me enough to want to know such filth like me. This is a truth revealed to me by God, and sure the Bible was a means that He revealed that to me, but if Jericho wasn’t a real city nor did that attack happen, that doesn’t change a truth of who God is. If you are mad at gravity and don’t believe in it, you will still fall off a building if you step off, even if the theory is proven wrong, you will still fall. You can’t change the truth of God, it is unshakable.
If you are just a Christian because of the circular logic that “the Bible is God’s word because the Bible says it is God’s word, and God is love because the Bible says so”, I would doubt your Christianity. I hate to do that, because only God knows our hearts, but God is so much more than words in a book. And the age of the earth or if Genesis is literal is so insignificant and unimportant to the main message. God is love because He is, that is a truth, not a Biblical word truth, a real experiential truth!