Am I overthinking this?Absolutely not!!! You’re asking very rational and intelligent questions. Having been a 2-channel audiophile for about 40 years (ugh) and looking back, I would’ve made HUGE (and very costly) mistakes if I just jumped in and threw big bucks down on what I thought I liked at that point. Look at it like wine — would you start with a $10k bottle or start lower and let your tastes/knowledge base grow and evolve before going big?
The good news is you can get some really excellent gear and build an extremely satisfying and rewarding system for not all that much these days, and even more so if you’re willing to buy used gear. First, and MOST importantly, you need to go and listen to various systems to start to identify what sound characteristics are most important to YOU personally (using your own music as well as some well-recorded demo material) and then you’ll be in a much better position to take a good first stab at putting together a system that’ll really make you happy. Then, as you listen to it for a while and hear more gear at shows or wherever, start to identify what improvements you’d like and upgrade one piece at a time until you’re completely happy (good luck with that part). Oh yeah, and READ as much as you can to learn more about both the technical aspects of audio and other products out there so you’re in a better position to make good choices later.
As a VERY basic guideline, starting with a $10k budget you could buy $3k speakers, $4k integrated amp, $2k source, and $1k for cables/misc and you could have a REALLY nice near-full-range starting system. Unless you feel highly confident in your ability to choose gear at that point I’d hesitate to spend much more than that (remember the wine example). Anyway, looking back and if I was to start over even with a big budget this is what I’d do FWIW. Hope this helps a bit, and WELCOME the the wonderful, awful world of higher-end audio!