That realisation came after a gruelling recording process for Osiris in Auckland, where he flipped burgers during the day and wrote and recorded at night.
He headed to America for three months, performed at Texas festival South By Southwest, crashed industry events, ran into idols like Chance the Rapper and attended the Coachella music festival. He also met rapper after struggling rapper.
Inspired, he returned to Cambridge, built a studio, and started work on 2077. Released today, it is, he says, the second of a four-album project with a futuristic sci-fi theme.
"The last album was post apocalyptic. The world's ended, and now people from Earth have gone into space and started a new civilisation," he says.
"2077 is about where they're at that point, with their new society."
It was inspired by news events that made him feel like "the end is near".
"There are a lot of terrible things happening in the world these days. I thought, why not talk about what's possible if you implement certain rules and beliefs into a new society and show people where we could end up?"
The results show Grimm is fulfilling some of the promise shown on Osiris, with woozy grinds like Foreigner and Pluto's Kurse mixing with clubby anthems B4eva and 2016AD.
The album's centrepiece, Sinse 7, is a piece of nonsensical brilliance in which Grimm acts like a hip-hop Dr Seuss across lines like: "I can do what I wanna ... shopping in my pyjamas, I could become a farmer / Riding around on my llama."
Grimm's lyrics stand out for their lack of violence and swearing - something predominant in the hip-hop art form - and there's a good reason for that.
"I don't agree with violence, I don't think it has a place anywhere," he says. "The world would be a better place if we weren't promoting guns and violence as much as we have been."
Grimm says it would be wrong to write songs about things he hadn't seen or experienced.
"I've always found it hard that I didn't rap about similar subject matters as other rappers as far as sex and violence and drugs," he says.
"Over the last year I've realised, that's me. I'm very comfortable with who I am and how I see the world.
"It would bother me if I was talking about things that weren't really about who I am."
Instead, Grimm finds himself watching sci-fi films - his favourite is The Matrix - staring up at the sky and wondering what life would be like up there.
As the hook for Sinse 7 goes: "I wish I was a navigator, flying through the stars in my spaceship."
Who: Cambridge rapper Diaz Grimm
What: Second album 2077, out today
