People who are obsessed with second-brain tools often accomplish the least because they are preoccupied with optimizing the perfect setup.
Notes.app FTW
Apple notes cannot even link to a different note. There's a lot of middle ground between linked Markdown notes and the dogmatic "build a second brain" stuff.
Hookmark app, which gives a shortcut to copy the formatted link, is all you need to link between notes in AN. They should release the mobile version soon, it's been in the works for some time.
I'm also on team Notes.app, but i honestly never got very good at consistent organized note taking.
My workflow is mostly:
If it's important i use my "first brain". I tend to be great at remembering stuff, which is probably also why i never really got into note taking. And yes, i still remember most phone numbers from my childhood, despite 99% of them having been out of use for a couple of decades by now :D
If i'm at my desk there is always pen & paper next to my keyboard, and anything "short term" gets noted there. That would mostly be meeting notes, questions (for meetings), and high level architecture sketches that will then go into a drawing tool at some point.
Anything else lives in Notes.app, but not as complex notes, but rather just a short sentence or link to an article on the web.
I also use the Apple Reading List for interesting articles i intend to read, but much like Pocket it is more a place where links go to die. I very rarely ever read anything i put there, so maybe i should just stop doing that :)
I have tried pretty much every "modern" note taking tool out there, including RocketBook (yes, physical), but none of them ever really "clicked" with me. Notes.app gets the job done, works well across different platforms, and integrates well into every platform i use.
And they never stick to one app long enough to get the benefits. Constantly switching, looking for better and faster. I switched to index cards, and honestly, I don't miss digital FOMO.