Wheels and tires

I have a 2018 and I wanted to get a lift. However I’m not to knowledgeable about the wheels and tires. The offset to be exact I wanted to get a 6 inch lift with 35’a when I went in they said I needed a negative offset. I was wondering if that is the case or we’re they just wanting to sell me for something higher priced? I wanted to get the wheels flush with the tires. Any help would be much appreciated.

 

If you want it flush go with a +25. Here is a -11 for reference. Be advised, you will wake up the next morning wishing you had gone with the negative offset ! Lol

 

I was looking for more of a look like this pic. If I want something like this what other mods are needed?