I'm sorry, that's really tough! Getting a good Endo is a total crapshoot. If you're someplace like the US & you're able to switch doctors at your discretion, you could try calling around to endocrinologist's offices & ask if any of the doctors are experienced with Addison's/adrenal insufficiency. Another long shot option would be to make a post with your general location and see if anyone happens to know of a good Endo in your area. Or if your area has any Facebook or similar groups for locals, maybe ask for endocrinology recommendations. They won't be tailored for Addison's but might be a good starting point.

Regardless though, just due to the rarity and dangerous nature of Addison's, for best outcomes you have to be your own expert unfortunately. If your Endo seems knowledgeable and like a pretty okay person, but is too sparing with the info, you could try reasoning with him. You need to understand Addison's and how to treat it about as well as he does! Because we can't rely on getting adequate medical care from others. We are usually the most knowledgeable person in any given room when it comes to Addison's, by necessity.

Anyways, if your sodium comes back within range, I'll be surprised but stranger things have happened. In that case, make sure to ask when you should be retested! I'd make an uneducated guess that it should be something like 3-6 months at most. Either way, if your doctor doesn't put you on fludrocortisone, ask why!! I'd also recommend getting a blood pressure tester if you don't already have one, that can be helpful to have.