Amazon just announced a new set of 4k TVs, including a "4-series" and an upgraded "Omni series".
I just stumbled upon the fact that the 50" version of these TVs has a 22%-23% temporary introductory price discount, making the Omni series $399 (normally $509.99), and the 4-series $359.99 (normally $469.99).
Note below the price on the main screen, it says the following:
Introductory price of $399.99 (22% off) will be reflected at checkout. After introductory period, price will be $509.99.
I'm not sure at the moment how long this introductory price will last. The deal does not appear to apply to any of the other sizes. The TV is set to ship on 10/27/21.
50" Omni link:
50" 4-series link:
Here is a link discussing the features and differences of each series: