Knowing which fast and performance-based themes for your child sites is something that can take time to research and test. A more recent theme that is clean lightweight and performance-based but has a number of modules built in even in the free version is the Suki theme.
After you have installed and activated the Suki theme on your child site it will add a new admin menu under;
Appearance > Suki
You will be able to find all of the available modules for Suki. Each of the modules can then be opened in the customizer. There is a pro version for Suki called Suki Pro which includes a number of additional pro modules. If you are also using WooCommerce on your child site Suki comes with a number of default options already for WooCommerce. In Suki Pro, there are a number of additional module options for WooCommerce.
Depending on which version you are using as well as which page builder you are also using there are a number of demo sites that can be imported. Suki has demo sites for Elementor and Brizy page builders. Suki will work with other page builders like Beaver Builder and SiteOrigin.
Brizy does have a child theme that can be installed for making custom changes on your site.
Suki theme is a clean and fast theme without a lot of bloat and is recommending to update existing or new sites if you have performance in mind.
