Quick question just to confirm, I'm a sunni nation and want to convert to protestant, can I do this via rebels and letting them force demands?
basically you convert a province with the religion you want, aka protestant. It is ideal to send missionary when you just conquered the protestant province. I mean, same day peace deal goes into effect. Then zealots will overrule seperatists. do not pay for missionary. lower autonomy if needed.
let protestant zealots spawn. move your capital far away from them, to other side of nation. Delete all forts. let zealots occupy all, and when they are busy sieging your capital, do a mass desieging of the now protestant provinces in your nation.
Then kill the zealots when capital is down, and accept demands.
the moving capital isn't really needed, but it makes sure the rebels don't enforce demands after 2 years, leaving your nation below 50% protestant. Ideally you start a war when the rebels reach 50% development religion conversions. Fight the war, and let the rebels occupy EVERYTHING. Then resiege everything en masse when they are sieging your capital fortress. Do this to avoid the +25% autonomy on zealot occupied provinces, when accepting demands. Note that you can STAY sunni when 100% of your nation is protestant, and assign/revoke provinces to dhimmi estate to trigger protestant zealots agan. the idea is to revoke dhimmi estate when they are already below 40% loyalty. this will trigger another protestant zealot stack, and you can accept demands and flip protestant at YOUR moment. his can be handy if you are allied to let's say ottomans, and you want to wait until the right moment to flip.
Switching from sunni to protestant (aka swithing your gov religion between different religious groups) will ANNUL ALL YOUR ALLIANCES, so when you accept zealot demands, make SURE uou got all your diplomats free to re-ally them the same month. if you don't do this, they will usually go neutral/hostile next month.
Done the above countless of times, it has no downsides other then rebels tanking your income for 5-10 years. I just did it as Andalusia offline, and will continue my campaign on twitch today as catholic andalusia with 100% religious unity
one note: rebels will teleport across sea zones to reach other unconverted parts of your nation. if the sea zone they are in is blockaded, they won't teleport. For example, portugal will block sea zone if zealots are near gibraltar. you can solve this by sending 1k to a sea zone province that is NOT sea blockaded, like Granada. The rebels wilmove in to KILL your 1k as soon as it lands from boats, and THEN they will teleport because they are now in sea zone that isn't blockaded. of course, move your boats OUT when 1k landed.
hope this helps.