Classic Widgets with Block-based Widgets allows you to use both widgets screens at the same time.
Sometimes, you need to use the classic widget screen for some of the widgets without permanently disabling the block-based widgets. With this plugin, you can access the Classic Widgets screen in Appearance > Classic Widgets and the block-based screen at the usual place in Appearance > Widgets.
NOTE:-
This plugin uses WordPress filters to create a new classic widget screen. That means it will work as long as WordPress supports the Classic Widgets screen.