My wife and I did not sleep trained our kids. They co-slept with us, they were happy we were able to sleep through the night. Eventually they transitioned into their own bed no problem. Our neighbors will let their baby cry like forever, it was excruciating and imo pointless.
I think parenting is the worst possible space for N=1 anecdotes. I have two sets of friends who did what you did and have never slept alone or through the night for coming up on five years. For our oldest, also coming up on five years, we did like one night of sleep training at 18 months and immediately started sleeping through the night like magic. For our youngest, we never had to do anything, he just always slept…
-everyone has an opinion about parenting, and many are not afraid to share it
-don't compare yourself to someone with an older child. You will start out a level zero parent, but you get a level zero baby. You'll level up with them. No one starts out a level 20 parent.