Anyways, here's an official reference post for my take on adult (22-23) Dib :]
I designed and wrote him as a sort of hypothetical "what if when he became older he finally got away from his horrible situation and finally found a group of people who actually appreciate his presence, got whatever help he needed to function and just overall became happier?" I know that's not typically how Invader Zim goes but I don't really care lol. I wanted to put a bit more emphasis on his sillier side we see occasionally in the series, since he's probably not chronically depressed and/or stressed all the time now.
I'm basing his style on when the show aired, as he would be 11-12 in 2001-2002 so this would be in 2012. I have a soft spot for older internet culture given I grew up with it so consider this a kind of homage to it!
"Zim you son of a bitch, who the fuck did you kill AGAIN?!"
"I thought it was a giant raspberry!"
Ok so random idea that I got: Zim learns about Earth berries for the 1st time in his life and then confuses human brain for a berry because of resemblance in form with some of them. And tries to surprise Dib with a "tasty" and totally normal gift :)
And obligatory traditional doodles. Have drawn Dib with this damn cup and later decided that Zim needed one too. The second is based on a song low key idk.