Britannia Only
Removes everything except the Empire of Britannia. Not sure why the rest of the map is Red but it doesn’t have an effect on anything as far as I can tell, played for over 50 years and didn’t run into any problems. This as you might expect also greatly improves performance. If you want me to make a similar mod for a different region let me know in the comments.
Known bugs:
Characters wearing HRE crowns, attempting to find a fix for this. Only known bug so far.