I know what you mean. When I started about fifty years ago, no question I was stumbling around in the dark. With lots of listening, research and a couple bad choices I learned some very basic rules and kinda had some clue of what I wanted.
I spent a lot of time in dealers, trying to figure out how you hear the speaker vs the amp, vs the preamp... etc.
Over the next couple decades, I researched and upgraded every five years or so... as my finances allowed. I traveled extensively, so was able to stop by an audio store here and there around the country. I became good friends with a couple audio dealers. Most importantly, I did extensive testing... borrowing a few different components. Also I did hundreds of hours testing interconnects and cables. I wanted to understand what they could do. I did detailed comparisons on variables which I had to figure out. So, from this I understood what mattered and how much.
Then I set out to get my ears tuned to the real thing. Listened to lots of live music, acoustic where I could, then ten years 7th row center symphony season tickets. Also, as I traveled during all that time (a lot) I listened to music constantly on the best available portable rigs... changing technology as it improved, always at the cutting edge.
Finally when forty years had gone by, I was really comfortable. I could walk in an assess the sonic characteristics of a system. I could detect distortion that is not directly heard... determine noise floor. I would understand how I would change it. I can imagine what components that I am familiar with will sound like. Most importantly the last two upgrades, I knew exactly which components I needed to get exactly the sound I was looking for, and each step along the way fell into place, exactly like I had envisioned.
I do not, by a long shot know everything. But I am really comfortable in building and assessing sound systems and acoustic spaces. It took forty years of dedication and experience. This is one of the reasons I like to forum. Questions are posed that I have never thought about, and it makes me think through things I haven't before. I learn a lot through these questions and some of the other experienced audiophiles that post here.
Reminds me somewhat of my career as well. By the end, I could walk into a huge project and with a minimum of meetings and observations assess where it was, if was it on schedule and if it was going to be successful (NO) and figure out exactly how to fix it.