In the Post editor with a block theme active and meta boxes present, zooming out doesn’t affect the meta box pane visibility. This may be seen as unideal because displaying as much of the post content vertically as possible seems to be an aim of zoom out. Zooming out hides the editor’s footer for presumably that reason (though maybe that has more to do with content-only editing). However, not a major issue as the meta box area can be resized to take up minimal space.

Demo of trunk