Loved the analysis! One thing I find interesting is the separation between your docs (box.com) and your bookmarks (Raindrop or Trello). In some cases it just doesn't make sense, since these can be very similar - videos on mp4 vs. YouTube, or sheets in xlsx vs. Airtable. Don't you think these should be organized together?

Hope you don't mind me butting-in, but I'd like to suggest another option - tagbox.io. It's early-stage but live and aims to organize everything in one place. Hit us up at hello@tagbox.io if you wanna try it out - I'd love to hear what you think.