Same problem, it was working fine and then it wasn't.  I've tried everything mentioned here and on other  forums and nothing works.

I just get the standard "Please know that we've received a similar issue of your concern. Our product engineers are working on a solution for the problem where estimates do not use the custom form style selected when sent to the customer using the new experience. The problem occurs when emailing an estimate, as it still includes the quantity, rate, and description despite unchecking them in the customer form style."

The standard answer is the engineers are working on it or I will bring it to their attention, very frustrating!!!