Personally, I think buying cheaper TVs or rather discounted TVs every 2-3yrs is the best way to go, if you don't mind taking some sacrifices with the picture in certain areas. That way you get something new to play with every 2-3yrs without paying an arm and a leg for it, but that's just my preference.
Generally, the cheaper Samsung TVs like the NU7400 are generally better in the smaller sizes from the reviews I've read, as the uniformity tends to be better. The cheaper LG TVs aren't that bad either, and the black uniformity in those can be slightly better than the higher more expensive nano cell ones which often at times use very flawed local dimming. The cheaper ones also can be direct lit panels rather than edge lit, without local dimming, and can sometimes be more uniform and less jarring between the light transitions in certain content because of this.
The cheaper Sony TVs are also not bad either.
It really comes down to what your specific needs are. If you need to have a complete black uniform picture, in a low lit room, then you probably need VA Direct lit LED penel with a large number of dimmable zones for local dimming, or you need an OLED. I think those are really your two choices for a black uniform picture.
Burn-in is a real thing.
