I mean, if it all it took to become a 40% shooter was walking tape I'd be in the league

Trent is a different player and athlete to GP2. GP2 is actually pretty similar to Shaq in terms of his track record and physical profile.
I think GP2 deserves a ton of credit for the work he's put in and his obvious skill level improvement, but the Warriors are also the perfect team for him. Everyone knew about GP2's defense, it shouldn't be a surprise that he's been so good on that end...but the Warriors offense is perfect for him to succeed in. They play a very unique style that allows for a lot of cutting. They run more splits and off ball movement than anyone in the league and it opens up cuts whenever the defense makes a small mistake, and there are a ton of them when they are chasing Curry around all over the place.
The Jazz play a completely different style and he wouldn't have the same success with the cutting and being a pseudo big man. We're all about spreading out and setting up a PnR action with Gobert. 90% of our offense is just creating angles for the screen and spacing out. If GP2's shooting is real he could make it work out anywhere, but I think it's important for these fringe guys to find the right spot for them to succeed. The Jazz offense doesn't require a ton to make it work either, but it's a different skillset. It's really all about the shooting. If you can't/won't shoot like Forrest it's going to be really hard to make it work here.
Stanley Johnson is probably gone for the rest of the season with the Lakers, but he would have been a decent bet. I personally am a believer in Oni, but if Quin has given up on him there is no point to him being on the roster. We need to snatch up a player with a Hinkie special.