it does not matter what i want or not. i only matters what the license allows and what it does not.

yes, you could have done that. CC0 basically means you can do whatever you want. it is like an international public domain (public domain is different in different countries, but the CC0 is the same everywhere).

as far as i know, there is no popular license to specifically disallow the resale of the asset. sites that don't allow the resale of the asset itself usually have a custom license. also if you allow the commercial sale of your assets in a game, then what about a game that has very little gameplay? like something that is basically a collection with all your assets inside a fps template. put the code in a separate - maybe hidden - folder and an asset folder front and center. that would circumvent your restriction. just allowing all commercial use or no commercial use is far simpler then anything in between.

the AI stuff is pretty knew and i am sure the creative commons people are already working on a license for it. no idea what that sketchfab license is, but it has a restriction that the CC0 does not.

basically you said: "everyone can do whatever they want without any restrictions, except selling them directly or using them in training an AI."
that makes no sense. just write that it can be used for anything with these 2 restrictions and remove the mention of the CC0.