UPDATED

The event chain has to be followed like this, with the following conditions:


Start as Brandenburg with your Wittelsbach ruler
From here there is 2 different paths:

Historical / Canon Path

1. Switch your vote to Bohemia and hope he gets elected in the first 10-20 Years
2. Bohemia's Luxembourg Dynasty MUST get elected and Wittelsbach HRE Emperor MUST die before you get to -20 "Wittelsbacher investment"
3. You MUST get to -20 Wittelsbacher investment (bottom option that starts at -15) so the Wittelsbachs will leave Brandenburg
Avoid the Askanier pretender event if possible (it's RNG) but it's not the end of the world.
Pick the historical option, if "WIttelsbacher Investment" modifier gets removed, you have to reload or restart.
4. You MUST have Bohemia give you one of his sons as Ruler (Jindrich of Luxembourg Dynasty, usually) which requires "Jehan The Blind" to be Emperor
5. Bohemias ruler ,Jehan The Blind, MUST die with his son, Karel taking over
6. YOUR Luxembourg Dynasty Ruler must die now, resulting in Bohemia getting an event to put Friedrich (his adviser) on YOUR Throne (This is the historical options ONLY FOR THE 2 STARTING SONS of JEHAN)



NON-HISTORICAL / FASTER PATH

1. Get to -20 "Wittelsbach Invesetment" as fast as you can.
2. The starting HRE Emperor from Bavaria (from your Wittelsbach Dynasty) MUST SURVIVE until you reach -20 "Wittelsbach Invesetment".
IF HE DIES JUST PROCEED WITH THE HISTORICAL ROUTE
3. The moment you get the event after reaching -20 "Wittelsbach Invesetment", press the only option and TAG SWITCH to the Bavarian Emperor.
4. in 1-3 Month ticks, Bavaria gets the event to replace Brandenburg's ruler. Here you MUST PICK the option to go with an EXPERIENCED ADVISOR (3rd Option, I think).
It is IMPORTANT you tag switch and pick this option yourself because for Bavarian AI, this is NOT AN HISTORICAL OPTION, SO THE AI WILL ALWAYS!!!! PICK SOMETHING ELSE.

Now Tag switch back to Brandenburg, the game will always generate "Friedrich von Hohenzollern" in these outcomes who will ALWAYS be 30 years old, NO MATTER WHEN you finish the event chain.

Tag Switch to the countries you get the events with to improve your outcome (like to Bohemia or Bavaria) and pick the response option you want, yourself (can take 1-3 months for the event to appear) . You can do this by enabling tag switching in the game rules and then hold CTRL+Left Click to switch country
Additionally, type:
AI ( to disable AI when you tag switch and dont want the AI to ruin your country while you are gone)
kill tag (kill BOH)
to kill Bohemias ruler via console to make it faster or trouble shoot the event chain yourself




If these things happen in your game, then you should be able to make it happen.
RNG is involved so i suggest either lots of saving and restarting will be happening.

This is the Event ID for Bohemia to give you Friedrich von Hohenzollern:
flavor_bra_dynasty.1201.a
flavor_bra_dynasty.1200
To open in-game console type
-debug_mode
Into your Launch Options in Steam



Leave me comments so i can update and make this more accurate