I believe you are conflating a lack of mastery with a lack of learning.
You have probably learned many things - but only long and repeated practice of those new skills will bring true mastery. That will likely take years - for all of us. Keep the faith.
Thanks, guys for your advice.
@monroemann, thanks for mentioning that book. Reviews on Amazon sound promising, so I ordered it yesterday . Looking forward to reading it.
Yeah, that’s what I feel when I focus exclusively on doing tutorials. Once I started building apps of my own, that feeling attenuated on its own.