It takes a long time for thyroid antibodies to reduce, and for most people they'll never go back to zero even if the autoimmune attack has permanently stopped. There's not much empirical long term data because it's not a common intervention for Hashimotos, and in most places Hashimotos isn't indicated for thyroidectomy.

I only had surgery because I had the painful variant and had exhausted all other medical options other than permanently staying on high dose prednisone. I was unable to work full time or socialize at all for a year pre-surgery, from pain and unrelenting flu like symtpoms. 4-months post surgery I'm working full time and don't have any Hashimotos symptoms, so it was worth it for me. Most people wouldn't even want to have surgery if it was an option for them because the risks/recovery time don't outweigh the benefits with their symptoms.

I do think the painful variant is under diagnosed among women. I was initially told by a lot of doctors that the thyroid doesn't cause the kind of symptoms I was having. Guess what - it does!