wrote: Something important to know:
4K TV's look great for 4K content but are a big challenge for standard HD cable broadcasting, especially live sports. 4K TV's have 4 times the amount of pixels which means that every pixel of a 1080i standard HD broadcast needs to be upscaled 4 times, 75% of the content you see on a 4K screen has been upscaled.
I have a very high quality Sony 4K TV and my Fios looks very good on 1080i channels like CBS, NBC, and my regional sports networks but looks poor on 720p channels like FOX, ABC, ESPN. 720p channels have always looked weak on Fios, all those weaknesses are amplified on a 4K panel.
So if you are thinking of upgrading from your old 1080p HDTV to a new 4K TV, understand that you are a) going to be taking a step back on picture quality with a 4K TV on the channels you may watch the most especially if b) you don't spend the money to get a really good 4K panel with exceptional upscaling capabilities.
That may be true of your Sony, it certainly was of mine. I can not speak to the Sony OLED's or the Z9D with their X1 processor's but I can speak for an LG OLED65B. I have FiOS with one Motorola DVR (7216) and 3 TiVo's using cable cards. A Bolt, a Roamio Pro and a Roamo HD. The 720 channels come is great upscaled to 4k via a Pioneer ELITE SC-90 or passed thru to the OLED directly. You would be hard pressed to tell the difference from 1080i.
The TiVo's have slightly better PQ than the Motorola DVR in my opinion.
That said LG does not do as good a job with SD FiOS channels as my KURO does connected only to a TiVo.