Sony is somewhat successful with their tv line using LG OLED panels thanks to their long experience in making TVs and cameras. People pay premium for their video processing
Apple doesn't have the same record. An Apple TV will likely end up being something like their air pods Max. Premium built, pretty good but not best image quality for the premium price, too expensive for people just looking for a nice TV, not good enough for videophiles, mainly appeal to die hard Apple fans.
Apple isn't going to make their own panels. Design wise, is Apple going to do better than the LG OLED gallery tv that looks literally like a framed picture. In term of software features, what can the TV do beyond a separate box that can be swapped for newer more capable hardware as needed. Hard to see the value proposition here