Are there in game cheats that don't disappear suddenly ? And are for the whole game ?
I only found cheats that are in game for a while and then disappear (skills).
Every Elector has an opinion of you. These are a spectrum:
Hostile - Negative - Neutral - Positive - Friendly
Friendly is the best opinion and for most/all of that range, negotiating with the Elector will typically result in them agreeing to join you without requiring a quest first. If you are told an Elector is friendly, and you had been planning to appoint them to your cabinet, marry or blackmail them, consider negotiating first to save precious social turns. (There are, of course, times when you will want to ignore that tip, just to see what happens).