Holding someone in guard is as simple as "how long can I lock my guard?".
There's nothing complicated about holding someone in your guard.
I don't need to mention wrist control or anything else involved because wrist control can't be recreated in a video game.
My coach was a HW Muay Thai champ and a BJJ Black Belt, he can keep you in his guard simply because his legs are strong as an Ox. Nothing complicated about it. The only complicated part is escaping the guard with the right steps.
Holding someone in guard with a Gi on, yeah maybe THAT is complicated, but No-Gi isn't.