The Basenotes thread is indeed epic in its breadth. Depth? I don't feel qualified enough to judge.
If I had to add a little:
1. Maybe avoid buying 3ml sprays straight off the bat. Instead, get the minimum size of more stuff (and if you can smell at the mall first; although watch out for exciting top notes to get you to buy, followed by a boring drydown), try them a couple of days each (never more than 2 at the same time), and explore what you like that way. Scent is ultimately very personal, a lot less "objective" as a field than, say, classic menswear. Where you grew up, with whom, what you did with your life all impact how you perceive things. And also what your partner will say once you've sprayed the thing! And I think you can't know until you've tried a lot of stuff properly.
2. I love to get insights from the great/famous names first, and use that as a starting point to spider my knowledge acquisition, particularly in very subjective fields. Who are big names who wrote about perfume? Roudnitska is well represented in that thread and probably the most prolific. JC Ellena is another one. Luca Turin is probably the biggest name on the review side, in part for qualitative reasons (for example comparing in detail vintage vs reformulations, and giving background info on perfumers), in part because he was one of the first to publish critical writing in an industry where ridiculous PR was the norm. Forcing yourself to read through his Perfumes book is one way to pick up many of the ideas and famous names/perfumes - my initial purchases were basically LT's 5*s. Roja Dove's book is basic, but I think a nice introduction. Both Roudnitska and LT argue that an artist or amateur should expand his culture in all fields in order to get a better appreciation of one (and LT even paired perfumes with classical music in one instance, touching briefly on the link between pieces and their perfumery counterpart). Creativity doesn't happen in a vacuum kind of thing.
3. the house and the perfume are incredibly dissociated, with some exceptions (Guerlain was a family-run business for a century with a very specific house style). Look at all the names that have done stuff for Amouage, or the places that Kurkdjian has turned up on commission before opening his house. So often, a brand means little in perfume beyond price point, and some houses (including at least one of those you mention) have gained a reputation of often "overcharging for cheap boring stuff". Now, a perfumer is, him/herself, a "brand" as well, and whilst they do have to eat and therefore occasionally succumb to the right bribe in exchange for knocking out a cheap formula built via market research, it can be quite interesting to follow the intellectual path taken by a perfumer over time (e.g. Ellena's gradual move to minimalism).
4. vintage is really worth it. Pre-1960s, perfumery like couture were for a very different market. Houses were run by dictatorial artists who accumulated taste and knowledge and curated their employees' work (or, in Guerlain's case, were often the perfumer). The works from that era are monsters of complexity and intelligence, and use natural materials which have since been banned and give them depth and a certain roundness you don't find with modern works as often. Some vintage are impossible to find e.g. Nombre Noir, Lutens' first. Others are cheap-ish because they were popular back in the days - Habit Rouge, Cabochard... def worth a try.
5. in the case of deciding not to bother with the hobby, it's important to note that perfumery is fashion driven and the very nose of everybody around you is going to change with the fashion, because exposition drives learning and taste as well. This much more so than with clothing, again. So you have to be careful to pick a set of mainstream scents that the people you interact with currently like, and unlike a Savile Row suit cut in a timeless classic style (whatever you think that is) it will not age well. Stereotypically, 80s were about projection, 90s about boring, aquatic notes, etc. (considering most perfumes today are designed via market research, and the market adapts to like what is given to them, makes you wonder about the feedback loops...).
"GLHF" as they say.
that's great feedback, thanks for putting it together.