This solution works! Though the changes aren't applied immediately as you change the frontmatter, you still have to update the editor first, for example, by typing something in. I'll tinker with a way to force an update on frontmatter change, and if possible to reduce computations of always checking the frontmatter every cycle.
Thanks to @liamcain for suggesting https://discord.com/channels/686053708261228577/1156305653460111460/1161382520814837882
This solution works! Though the changes aren't applied immediately as you change the frontmatter, you still have to
updatethe editor first, for example, by typing something in. I'll tinker with a way to force an update on frontmatter change, and if possible to reduce computations of always checking the frontmatter every cycle.