They have done other appearances. The official podcast even has a post-finale (day after it aired) interview at NY Comic Con. The CEO of Amazon studios talked about Rings of Power at Mipcom. Even House of the Dragon hasn't said what they have in store for the future. All they have said is they won't return until 2024 and a few general plans. You are holding Amazon to a standard that practically no one follows. Amazon hasn't even talked about future seasons of their other shows right after a season ended.
https://variety.com/2022/biz/news/lo...gm-1235408282/