Ha well, my hurdle was just understanding how all the different notes + links worked together, were set up etc. That's why I mentioned wanting a campaign to reverse-engineer, just having a little generic skeleton of a thing with all examples of linkings etc; that's how I learn best. Unfortunately the Obsidian TTRPG tutorial didnt help me much because even there they didn't provide a premade generic campaign to load up and tool around withIf you're interested in giving it another look, I would recommend not attempting to begin with a fully-fledged campaign management system.
I originally pickup Obsidian.md + sync simply because I moved to Linux and the sync tool offered me a replacement for google drive syncing.
I then started making use of some of the basic note and linking systems -- no plugins, nothing special at all really, just arranging some very simple, nested notes for a fairly straightforward campaign.
Then I realised I could probably do more with it, to help me set up a new, more complex sandbox campaign I've been planning. I started installing some individual plugins that looked useful, and working out how they work individually. Stuff like the initiative tracker, fantasy statblocks and encounter builder can all be used without needing any huge overall setup. I also added Leaflet for my main map, and started adding pins.
I have been using Obsidian TTRPG Tutorials - Obsidian TTRPG Tutorials to help me get a handle on each individual plugin.
The overall campaign material is just folders and notes I've built myself in a sensible folder structure. When I was ready, I looked at metabind to start adding quick-linking buttons for some rules material, which I was setting up myself. That said, you can do the same thing with just regular links and next to zero skill. Again, it was Obsidian TTFPG Tutorials got me onto the idea that I can create a note and pin it to the main left side panel to have a quick access system. But I didn't need something someone else built -- it's just a note, and I can add whatever works for me, however I want.
In the end my system isn't going to be anywhere near the complexity (or prettiness) of one of Josh Plunkett's vaults, but I don't need all that glitz and glamour, I just need something functional, and I'm adding bits and pieces one at a time, so I don't need to worry about how a bunch of different plugins are all interacting with one another or understand them all at once.

Example: in FoundryVTT, say I want to set up the effects etc for a Periapt of Wisdom- I won't look up what values and commands you need to make it work, I'll look at Gauntlets of Ogre Power and see how it's set up there, now I know the VTT mechanics for setting up an item that sets a stat at a certain number.