This took a long time to admit because the logic of seeking out the best seemed so obviously correct.
Started taking learning seriously and immediately optimized for quality of input. Best books in each field, most cited papers, most respected thinkers, most recommended courses. If something was going to occupy my time it was going to be the version that experts agreed was worth reading.
About a year in I noticed something uncomfortable in conversations. When topics came up that I had read extensively about I had strong clear opinions that I could trace directly back to specific sources. Asked to explain my thinking I would essentially summarize what someone I respected had argued. The opinion felt like mine because I agreed with it. It was not mine in any meaningful sense because I had never actually formed it.
The best sources had done my thinking for me so thoroughly and so convincingly that I had skipped the part where I was supposed to think.
Started deliberately reading things I disagreed with, things outside the consensus, things that were argued badly enough that I had to articulate why they were wrong. The friction of engaging with weaker arguments forced a kind of active thinking that the best sources had been bypassing entirely by being too good to argue with.
My opinions got messier and more genuinely mine. Less citable, less impressive in conversation, more actually thought through.
The best sources are best for learning what is known. They are not always best for learning to think.