I highly recommend Amadeus Pro by Hairersoft. It’s a very sleek tool for stereo audio editing and allows very customizable batch processing.
You can create batch templates and then drag and drop folders. With options to save as file types, append name variables, delete original or not, and even add processing such as fade ins or normalization.
Try it out. It was the first program I bought for my first Mac back in 2006! (There have been updates. Haha.)