I'll give you the gist. The exact recipe doesn't likely matter. Follow any good sourdough bread recipe or YouTube video for the most part. If you don't make sourdough bread normally it will take a lot of trial and error to get good at it.

I think what makes the difference giving me this amazing flavor is that I'm using 40% fresh ground wheat flour, and I mean fresh (within an hour, the flour was turned into dough).  I sifted out as much bitter bran as I could, and then ground the flour a second time in a hand-crank grinder to make it as fine as I could.  The remaining 60% was standard name-brand supermarket bread flour (Edmonds here in NZ).  I've used home ground flour before but I made the mistake of using it days afterwards.  Flour should either be aged (at least 2 weeks to stabilize, and this gives very good extensibility and gluten forming properties, better than fresh flour, and preferred by bakers) or very fresh (and this gives the best taste at a sacrifice of some extensibility and gluten forming).

Anyhow, also low innoculation (6% starter) which might not matter but that I what I did, it takes longer to bulk ferment. And a retard in the refrigerator during proofing to slow the fermentation.

The loaves weren't perfect, I didn't get as much oven spring as I wanted, but at this point I don't care about that.