I've never used it, but I believe Standard Notes has a feature whereby you can set a default view on a per note basis.
Personally, my view is that the split screen for markdown and preview is a waste of screen real estate, so my primary suggestion would be to implement a Typora style editor.
However failing that, being able to set a default view at individual note level I think would be a good compromise. That way, you could have the split screen view whilst compiling notes, but once a note is finished, you could set it to the preview view.
The reason I believe this would be a good feature is that when I revisit a note for reference, I just want to see it in a nicely formatted view, I don't want to see two screens showing me the same thing.
I'm not techie, so appreciate I may be asking something that is a lot of work and understand if not on the radar.
Thanks.