@kline - Unfortunately, the trigeminal nerve is the nerve that causes pain when you have TMJD & is the same nerve that causes very similar/identical symptoms w/ ES so it can be very hard to differentiate between the two. TMJ doesn’t typically cause sinus pain/symptoms, or skull base/back of the head pain, but ES does. You are wise to carefully consider whether or not surgery is right for you as it is a major surgery & takes time for full recovery. If your symptoms are tolerable, surgery should wait until a time when your symptoms begin to affect your quality of life.
There is series of videos on YouTube called Two Minute Neuroscience with one video for each of our 12 cranial nerves. There are 7 of those that can be irritated by elongated styloids/calcified stylohyoid ligaments. You will learn a lot about location, function & symptoms of dysfunction of those nerves by watching the videos. The nerves in question are the facial, trigeminal, glossopharyngeal, hypoglossal, accessory, vagus & vestibulocochlear. Here’s a link to get you started:
Another valuable resource is this post which @Jules made describing symptoms of ES & their causes: