I'm a purp. I came from ~5 years of wrestling pre BJJ.... The way I rolled while I was a white belt and knew I was better than most white belts was to learn how to use my wrestling in BJJ. The only time I "panicked" was when I was on my back and I did become scrappy then but never "100%" I've actually kept that mentality for all training.

Throughout my white/blue belt days the way I trained with upper belts was like playing a game of chess, we both know we can go 100% and compete with each other, or we could play BJJ and figure things out. The way I rolled against white belts when I was a white/blue belt was literally to match their energy. I rolled calm more times than none but if I sensed someone upping their intensity I'd match it.

The way to prepare yourself for a competition (I train at a competition gym fyi) is to roll with people who are also competing or know what it's like to compete and let them know. You're prepping for a competition. This won't mean you will be rolling at 100% but it'll be intense enough for you to carry over.