I already replied to a different thread, but figured I'd comment on some of the other options too. My vote is for Silverbullet, but I've tried way too many note taking tools.
Joplin: I ran into multiple syncing issues that caused data loss and large numbers of conflicted files. I'm pretty sure these were all fixed a long time ago, but it was annoying. The dev was always good about fixing issues when they came up. It takes forever to sync on my devices and only syncs while the app is open with the screen on. The format it exports markdown files in isn't standard, so I had to write my own scripts to export from joplin to markdown and preserve metadata.
Standard Notes: I was willing to pay for this, but it's extremely slow. Their support said it's because it loads everything into memory, which I'd expect to be terrible on mobile with large databases. It's also pretty limited in what you can do on the free self-hosted version.
Obsidian: I really like obsidian's ui/ux, and my only complaint is that it's not OSS. I'd even be happy if they offered a self-hosted sync solution. There are some third party solutions for syncing, but they aren't as smooth as the paid sync.
Trillium: I love Trillium. I would vote for it, but it recently entered into maintenance mode. The community is working to start a new fork and I'm sure it will be great, but it's too new to know where things will go yet. Trilium lets you encrypt specific notes and also has a cool plugin system where the plugin scripts are just notes in the database. It does have a mobile interface, but it's a bit limited compared to the desktop interface and also doesn't have an option to sync notes to use offline.
Silverbullet: My current choice. I use it between windows, macos, and an android phone. I leave all three clients on sync mode all the time. The interface is minimalistic, but offers everything I need for notes and documentation so far. One of the rare "markdown" tools that actually save your content to markdown files and not to a database with the ability to export to markdown. It also has a cool feature built in where it indexes all of your notes/tasks/paragraphs and lets you build queries around them sort of like the dataview plugin for obsidian.
Emacs: I haven't seen emacs mentioned yet, but emacs+org-mode is still great. The mobile apps just don't live up to the desktop experience, and you'd still have to figure out how to sync your notes yourself. Logseq's outliner format is a similar feel afaict