Regarding the achievements, there are many that only unlock if you are playing a certain difficulty or ruleset. It’s not difficult to disable achievements while cheat codes are active. Plus people who are cheating with achievements (or high scores) often just fake it entirely and just send steam a fake score or achievement unlock, or use 3rd party tools/mods to do the cheating so the game can’t even filter cheating vs legit achievements.

And this reminded me of a parallel to cheats offered by paradox games: custom rules. With CKII, you can create custom rulers without any limits. It’ll say “don’t go above this score if you want achievements, otherwise do what you want”. You can even replace every single ruler in the game with basically mortal gods before you start and switch between them at will if you don’t care about achievements, or replace everyone else with sickly imbeciles and dominate them all until they start dying off and getting replaced with normal characters.

And mods are another direction customization and replayability were taken vs using cheat codes.