My main issue with Obsidian is the steep learning curve because Obsidian is not self-contained; it needs many plug-ins, templates, and customization. I tried to keep things simple but it seems that to be useful you need Better BibTeX, Zotero, Zotero Integration, Pandoc, DataView, and so forth. All of these have their own learning curves and configuration, so it's a slog to get started. Obsidian seems designed for people who enjoy extensive customization and tweaking.
My second issue is that Obsidian is very free-form, so you need to decide on an "ideology" of how to use it. Do I want to go with Zettelkasken or Johnny Decimal or organize in folders or organize with tags or use Maps of Content? So far I feel like I'm ending up with a mess of notes, which isn't really helping me.
I started using Zotero at the same time. I highly recommend Zotero. It's essentially a PDF organizer and document citation system. Before Zotero, I had piles of PDFs in various directories and I couldn't find the information I wanted. Now I click in my browser and Zotero downloads the PDF, does OCR, auto-generates a detailed citation, makes everything searchable, and lets me annotate PDFs and take notes. Zotero is straightforward and has been a big help to me.
Zotero and Obsidian are commonly used together, but I haven't got the hang of the integration, so I'm open to suggestions. Specifically, I have notes and annotations in Zotero. Then I import everything into Obsidian and have a copy of the record in Obsidian. Now I have duplicated data. How do I keep things in sync? Should I be doing all my note-taking in Obsidian, or use Zotero's notes for a first pass through the document, or keep some notes in each?