I don't really have a desire (yet) to try all these fancy, modern boutique/craft variants.
3.) Most importantly ... could you recommend an old-school *must try* soap that I could work into my rotation?
Personally, I have no experience with soaps that satisfy your requirements. I do think that Zingari Man Sego is fantastic (I have the Nomad and love it). There are other modern soaps too, but then that gets into the 'fancy' variants you didn't want. Perhaps that is what you what you may want to explore though?
To go a different if expensive way, Martin de Candre is one of my favorite soaps. Vegan and essential oils only. Not fancy or craft. But expensive for a tub, and modestly expensive for a sample. Not expensive, imo, in terms of the longevity of the tub and number of shaves it delivers (as is uniformly acknowledged).
In the end, I hope you can enjoy the shaving adventure you are now on.