How to display posts by categories in Hestia
If you want to display posts from a particular category only in the Blog Section of Hestia then we've made a small extension that can do it.
You can download Hestia Blog Extension by clicking here. You can download the .zip file of the plugin from there. Once downloaded, you can install it on your WordPress by following this tutorial here.
After you've installed the plugin, you can navigate to Appearance > Customize > Frontpage Sections > Blog to see the category settings.