Indeed. Changing the value of the renderer option called “includeFeaturedInPosts” to true should help.
So, all you have to do is edit the config.json file available in this location: Documents ▸ Publii ▸ sites ▸ YOUR_SITE ▸ input ▸ themes ▸ YOUR_THEME
To preserve your custom code and prevent it being overwritten the next time the theme is updated, please ensure that you have created override files; these are, essentially, copies of the existing theme files that are stored separately from the main theme files → https://getpublii.com/dev/theme-overrides/
Ps: I will update the theme with the upcoming Publii release.