To be fair, Caddy's docs aren't great either. Last time I tried to deploy it to give SSL to something that didn't have it, took me 2 hrs to figure out the docs enough to get it working.
Caddy 1 docs felt handcrafted for each use case it supports, whereas Caddy 2 documentation feels generated, except for a couple of pages, which is enough to cover 99% of my needs.
I also think Caddy 1 was just simpler to use in general, so it didn't matter as much. But I don't have much experience with that version, so could be wrong.
Time and trial-and-error is what eventually solved it.
I was trying to configure the auto-HTTPS functionality to use DNS challenges, because my setup forbids any of the others, and this apparently requires plugins that are only supported by community efforts, so that's probably why I had such an issue.
The docs around configuring this were not immediately clear to me. Its like one part is over in this corner, the other over there. And the part about DNS provider plugins is off in a completely different direction. I definitely think things could be better organized. Also your one tutorial for getting HTTPS support only mentions the very basic cases. I think it'd be beneficial to see some more advanced tutorials using for instance some of the other LE challenge methods, something like this definitely would've saved me some time.