“Gold Multiplier” only works for gold income every turn.“Infinite Character Exp”, “Infinite Character Skill Points”, and “Reset Skill Points” take effects when opening character panel and work for that specific character.
If you want easy win, use “Drain AI Factions Army Size” before entering battle. Ctrl+Num 4 – Max Faction Specialisation (credibility, unity, heroism, intimidation, etc)