I see a lot of nice recommendation for note taking apps, but for me the 2 biggest features that I need are

1. No vendor lock in. I can’t lose access to my notes because of random account bans or the company going under or w/e. Also plain markdown, no nonsense proprietary formats.

2. Platform independence, I work across mac/windows/ios on home and work.

So I ended up using a git repo with markdown files. I use Noteable and Typora on mac/win. No need to import/export anything they both work with plain markdown files on the fs with tags as markdown front matter (I sync manually with git). For mobile I use GitJournal which basically has the same features and it can automatically sync with a git repo.