I just installed this CSS as a snippet, and it does exactly what I wanted. It keeps the properties out of the way but doesn’t outright disable them in case I need to reference them.
This is one of the things I like so much about Obsidian. If something isn’t quite to your liking, there’s a good chance someone has already written a plugin or snippet to tweak it.
I’d love to use this plugin: auto folds the properties by default in source view upon opening a note: Fold Properties By Default by @tbergeron (GitHub page)