Sounds like you're just having traction issues. Don't drop the rear suspension on its own, you may develop steering issues.

I'll assume you're using rubber tires. Make sure the ride height is the same front and back. 1 mm or so higher in the back is ok. Then try softer rear tires and/or softer rear springs. Conversely you could stiffen the front with the opposite as I suggested on the rear. Depending on your surface traction ideally you'd like the rear of the car a bit softer than the front. There are other things that could be done but baby steps.

Welcome to RCTech btw