You can safely use regular toilet paper that is septic safe in your RV toilet without any problems.
The difference is though that RV specific toilet paper is designed to break down faster in the RV toilet and chemicals than regular toilet paper does.
But I've used regular household toilet paper in an RV for years and never had a problem with it and RV toilet is more expensive to buy than regular toilet paper so that's one reason I use regular household toilet paper in an RV that's cheaper.