This issue is specific to the WordPress plugin stack and does not affect SaaS installations.
Widget areas are special places on a classic theme that can accept blocks — typically areas like your sidebar or footer. This guide will explain how to use widgets on your website.
Sites using modern block themes do not use widgets, so you won’t find Appearance → Widgets in your dashboard.
Without a theme that supports widgets, the only place you’ll get Appearance -> Widgets support is with the Power add on for the Store Pages “no store page” template. The “no store page” template has not been updated to use blocks instead of widgets.