Lord Zardi the rebel scum are forming a resistance , what shall we do ?
Crush them, rebels are easy.
Or you take humanist ideas and stack rebel reduction.
Otto's if they take say administration, influence , military idea, humanist as first four ideas that's the we want to blob the most as otto's.
Otto's going quantity, economic, offensive/quality and trade gives you the best troops along with the economy to support them.
One could replace trade with religious.
That lets you stack policies as well.
Religious/quantity 10% morale
Economic/quantity 10% dev reduction
Economic/offensive 10% cannon
Economic quality 5% discipline
Religious/quality 5% morale
Those 5 ideas give you best army in game.
Trade/quantity 20% goods produced.
Trade/quality trade efficiency
Add that as 6th idea you're rich, or take it earlier. Otto's don't really need the best army in game until after mil tech 16./ Even then vs ai quantity is fine.
Crimea, Serbia can make good marches if your going for the influence blob thing. Khorasan in the east iirc.
You get a huge chunk of the middle east as accepted cultures. Basically just follow your mission tree. Vassal feed Syria to keep your AE down. By that I mean first war vs Mamluks just take a couple of Syrian provinces and some dirt in Egypt.
Second war use reconquest cb, feed Syria the cores and annex.
Avoid wars with France if they have elan unlocked. Western europe can be ignored for the most part unless you're going for a mega blob. Can vassal feed Barcelona and early war France (before Mamluks).
If your economy can support it perma war with mercenaries is also doable. Just have to spread your empire around, have the economy to do it.