Just a question, how can I declare Independence without my realm shattering apart? this is because the top title of my realm is a Frankish duchy while my character is of Romano-Gallic culture.
My realm in show vassals
https://i.imgur.com/xQoBKiy.png
After winning the Independence war
https://i.imgur.com/jU58PwK.png
Also I tried to create the title right after I won the war and before the de-jure events can fire, but no luck
https://i.imgur.com/NjHdQJf.png
You could simply mass revoke all your vassals titles, and then declare independence. Then just give all those lands to new vassals once you're ready.