Well it depends on what you mean by cheating. Cheating tends to be a concept where more than one player is agreeing to a single ruleset and when one of those players breaks that ruleset, that's the cheating.

You cannot compete in a system if you don't both work in the same system. How do you know who's won in a game of chess for example if the other player is playing as if all of their pawns are queens, and you are not? From their perspective they won, but from yours, they didn't play the same game you're playing.

So it changes when you play a game by yourself. In my view, the ruleset was created by the developers. Now clearly you could say that maybe the devs wanted additional rulesets and didn't have the time, money, or inclination to make them, and you could also say that some devs are actively accepting of alterations to their game, but you have to ask yourself then what the rulesets of that game really are.

For me, and this is just for me, even when the devs themselves make sweeping changes to a game I can lose interest - especially when those changes "dumb down" the content and make it more accessible/simpler. Take mmo's for example: If for 2 years the game required other players and a lot of time investment and then suddenly the devs make a huge patch where you can now solo everything and achieve the same past accomplishments in a quarter of the time, I feel like that's "cheating". Generally I just quit when that happens.

Obviously this isn't an objective thing here, it's just my personal opinion. I think generally the original vision of the game is the "intended" vision, so altering it in certain ways just seems like it's going against the spirit of the game itself.