When I run composer require 'drupal/metatag:^2.0' 'drupal/schema_metatag:^3.0' everything appears fine, but I get an AJAX error when I try to open the meta tags widget on the page of a pre-existing node (though I couldn't find any helpful messaging). I see a little spin, and then nothing happens.
On a new node, the widget seems to work okay.
I'm not sure where to go from here; for now I've just rolled back those updates. Thanks!
Closed: works as designed
1.1
Code