Yesterday, I finally did it.
I was working on a post about my first impression from setting up at DesignerCon. I was in a bit of a hurry, because we were heading back to the convention last night, and WordPress kept losing my title. (I had updated the Gutenberg plugin before starting the post, and this had nothing to do with changing the permalink. The title, itself, would disppear. Just poof right out of existence. The new permalink field in the document sidebar, however, worked just fine. Unlike the editor's permalink field—the one just above the title field—the sidebar field caused my permalink settings to be saved, even when the title was nowhere to be found.)
Exiting the editor (after saving as draft), then re-entering the post editor through the "All Posts" page fixed the issue, but it also left me even more doubtful about continuing with WordPress, given its current trajectory.
So I pulled the trigger. I made sure that all of my posts that I actually wanted to keep were saved/updated in my Grav installation, deleted my WordPress installation and database via Softaculous, changed the settings on my Grav pages so that they were no longer password protected, and moved Grav from a subfolder to my public root.
I expected to encounter problems along the way, but nope! It was all smooth and easy!
And here we are. It's too soon for me to tell you to go try Grav for yourself, but I can tell you that—at this very early stage—I'm happy that I made the switch.