Yes, If-So can be used with Brizy.
You simply create a trigger with several content versions inside If-So, and paste the trigger shortcode inside a Brizy Shortcode or text element. Upon page rendering, the shortcode will be replaced with one of the content versions you created in your trigger.
If-So arrives with a WYSIWYG editor (the classic WordPress editor) that allows simple content editing. If you want to design your dynamic content using the Brizy editor, you can create the desired content in a new page or post, and then apply the content of the page (or post) you created inside the If-So trigger using a simple shortcode.