Just today I was thinking of this for Bear to avoid installing another app, and Obsidian just implemented this.
This will be the role of Lettera, currently in beta, offering the same Bear editor experience we all love.
Another subscription to open ad external markdown file? 
1 Like
You can import MD-files into Bear as you can export them. If that’s too tedious for you and you don’t want to pay for Lettera, you still can try an open source md editor like Mark Edit. You’ll just have to do without the familiar and cherished experience.
The business model of Lettera is not known yet.