I don't consider single player changes cheating. For something to be cheating, you need to break the rules agreed to by the players. If you're the only player, you presumably can't break the agreement you make with yourself.

I would further argue that it's a bad behaviour only if one cheats in competitive multiplayer games.

Almost a decade ago, I was having fun playing Left 4 Dead 2. There is this survival mode where you and your human teammates play against neverending waves of zombies. In one stage, there was someone who invented a way to defend yourselves on a bridge by all four players strictly crouching and shooting straight to the front, at the far end of the bridge. If anyone runs out of ammo, they walk a few steps to pick up a new M4 and come right back. Cooperation is the key in surviving for more than 15 minutes, and everyone must strictly obey this play style.

Anyway, the way to communicate between players were limited. It was hard to tell everyone what to do by typing. I downloaded a mod which grants us infinite ammo, that way, nobody needed to get up to get a new gun. In late game, there were three Tanks spawning and charging at us, that even with perfect timing it was hard to defeat all three. The infinite ammo absolutely helped, and I think I just created an new way of playing this stage which depends more on one's knowledge than skill.

I ended up had a great time with those strangers who played with me, who unlocked the gold medal of that stage, and way beyond the survival time requirement.

I've never heard anyone but you call modding a Bethesda game cheating.

Here's my definition of cheating: The use of any 3rd party software, not allowed by the developer, that gives a material in-game advantage to the user against other players without their knowledge or consent.

So mods are not cheating. Purely single player hacks are not cheating. Optional 3rd party overlays or in-game aids like RuneLite for OSRS or the many external deck/stat trackers for games like Hearthstone or Genshin Impact also aren't cheating.

Using Aimbots, wall hacks, infinite health/ammo/lives, and similar in online comp play is cheating.

Grey zone stuff would be things like unapproved in-game overlays.

I don't care what people do in single player. Hack and mod as much as your heart desires, it doesn't hurt any other players. The worst thing that can happen is you "cheat" yourself out of a personal challenge, but that's your own call.

I hope everyone is talking about online only. Most single player games have difficulty modes so you can play casually or hard as desired. This thread sounds like anything but the hardest is cheating though.

I think people who get angry at cheating/modding single player games are not to be taken seriously. Probably children.

Modding an offline sandbox game just to improve in-game quality of life is not the same as using cheat mods to get even at another and farm all the achievements for everyone to see.

I believe actual cheating requires there to be harm done to another player be it due to unfair advantages, theft of time or other malicious activity.