I just keep a central .bib database where I store all my literature (mostly academic books and articles). They all have a unique citation key and, if I have the pdf, are auto-filed according to certain rules that I can set.
In Obsidian, I use the Citations plugin to create literature notes. I name every note by the citekey (but this is just how I do it; you can name it by the author, title, etc.), and then include the citekey, author, and title in the file itself (you can set up the Citations plugin to do that automatically for you). I also have a link in the file to the pdf (if I have one), and then make whatever note I want to about the paper in question. (I also have my pdf highlights exported to .md that I paste there, with links to the appropriate pages.)
This way I can identify the lit notes very easily. If I need any info that’s not included in Obsidian (publication year, whatever – you could also include these I just try to avoid clutter), I can always look it up in BibDesk. When I want to refer to a lit. note, I use the markdown citations format [@citekey], although I do my final writing in latex so these will get exported via pandoc.
Beside the literature notes I also sometimes have some snippets from a work – e.g., a good quote, or something I want to remember. Then I create a separate note for that, and link to the appropriate lit note from it.
Anyway, I’m sure there are a lot of different setups that work well, I’m just used to this. It requires a few different programs (BibDesk, Pandoc, Highlights – which I use for pdf reading), but it works very well for me. I do think though that it is very worth using a dedicated reference manager, no matter how you set up your system.