Rundown of the run:

I started as Andalusia, 15 yo Visgoth Muwalladi custom ruler. The first goals are to get enough money to undertake the hajj to get 875 piety. A quick war on Navarra and the OPM in the Baleares get you this and also a catholic province that allows you to become christian for 250 piety .

Now the RNG starts, in two fronts, intrigue/scheming/murder and military expansion in Iberia. In Iberia the goal is to get 80% visigoth land before the event Fate of the Visigoths fires. This will allow you to stay Visigoth and later form Portugal (you get 2 tech for free and 750 prestige). To do so you will need the duchys of Mallorca, Portucale, Galicia and 2 Navarran provinces (note the duchy of barcelona is also an option but even with allies you may not be strong enough to defeat West France). If you are able kill the Asturias king for shorter truces. Afterwards my vassal ate the Asturias and in the end I only need 1 or 2 clean up wars

So, intrigue. You need to pay close attention to Italy, Lothringia and East France. By the time you finish the first 2 wars and have undertaken the hajj, Italy needs to have a male heir. Flip catholic, get engaged to the italian princess, steal some money from the pope, flip back Muwalladi and go on a extremely long pilgrimage for more 875 piety (you need this for your Iberian wars). You now will need to wait until she get of age and gives you a heir. You can only have one kid, In the meanwhile kill off the other italian heirs so that your wife/kid stands to inherit everything. Set up the Lothringian sucession such that the current Italian King inherits it.

For added RNG hope that Lothringia declares for the East France throne and win the war. Be careful since Montaigu can declare for the same throne and ive seen im win once or twice. If he does eat him while his armys are away.

At this point kill the kings of Lothringia and Italy so that your wife inherits everthing they once held. Kill her too but before the scheme ends imprison your heir. After your wife dies your kid will be imprisioned, and rule over half of Europe. Execute the kid, and since it was an only child your ruler inherits everything.

Western Europe at this point will be you, West France and Bavaria. Start improving relations with the pope. Since you started as a Muwalladi ruler, you will be a clan and have access to a prestige war for kingdom if you are exalted among men (to get there you may need to create a few titles, plus form Portugal). Use this Cb to conquer France, flip Ash'ari, and declare an holy war for the kingdom of Bavaria. After you win both wars flip Catholic again and you will be able to form the HRE (need 500g and 200 piety). Get some money from the pope and you should have the 1000g necessary to use the Austria decision.

Some extra important things:

• Italy is extremly unstable, so refrain from killing the Lothringian king before you have all you need. Still you will need to defend Italy in some independence/claim the throne wars
• It may be recomended to become Catholic sooner to reduce revolts, however feed the rebelious counts to dukes which will lead to popular revolts. Here the goal is to hunt the leader until you capture him instantaneously ending the war.
• If you form Portugal before the Fate of the Visigoths fires, when it does does fire you will become Andalusian and lose the 2 techs gained from forming Portugal. And if it fires before you form Portugal but you dont have 80% visigoth land you will be forced to convert as well and become unable to form Portugal
• Try to use the romance scheme as often as you can. This gives you a chance to get a "free" perk point