Thanks for sharing your experience, Brandon...
The greatest take-away from your post is the importance of "doing the work." Early on in my audio experience, I hooked up with passionate, energetic music lovers that were excited to do the work necessary to achieve great sound. My 80's brick & mortar dealer removed his living room picture window to install Altecs, for example. My 90's mod engineer/friend would spend hours testing isolation approaches, including those "under the hood" of gear. And yes, changes can prove sideways or negative, but, until you try.
Efforts are always rewarded. A great preamp in a specific SYSTEM may prove best, or not. Often, compromises need be made often due to mixing digital and analog gear, whether it be volume controls, wiring approaches and room requirements in placement. In recent years, I've learned room/loudspeaker integration to be most vital. Study, experiment with tuning a room (laser ruler a must.) Arrival timing, room resonances, bass nodes, ceiling and floor bounce, distances between and to your speakers, the tilt of the speakers in how that relates to your listening height. Experiment, experiment. When you find *** IT ***, once found, "it" ...will be readily apparent to you. THEN, everything you do upstream will take on much more life and character in your system. Experiments with wire, electronic gear, contact enhancement, isolation will begin to reveal themselves once those windows open.
And yes, many of these things cannot be measured, however, we each own the best testing devices ever created. I'm squarely in both camps, measurements indeed matter, known science matters to get close, THEN the fun work begins!
Some experienced listeners seem to have personal favorites in what's most important to address, often, impressed by some specific game changing experience in their journey...amp, TT, speakers...you name it. Often, that can become the "focus point" for individuals, however, as many have voiced here, everything does indeed matter once the windows open to great sound. Experiment, experiment.
Think Positive, Test Negative More Peace, Pin