Hi,
I can see that Sage has post formats enabled by default:
add_theme_support('post-formats', ['aside', 'gallery', 'link', 'image', 'quote', 'video', 'audio']);
However, there is not way to choose a post format on a post edit page. WP Codex states that once enabled, post formats should be selectable from edit screens.
Isn’t add_theme_support
perhaps called too late in Sage?