God I hate shopping for TVs. If my current one hadn't borked itself I think I'd have kept it forever.
Can't you disable automatic dimming? My current TV doesn't have this issue, although I disabled the dynamic contrast stuff day one.
It'll be that your TV can't go as bright then. It's typcally a problem that people have when the backlight is too high, or they are watching HDR content where the bright areas can create s little blooming. Disabling local dimming will stop it getting as bright And stop the dimming so the blacks will be more grey -as a standard LCD will be.
Therefore I would expect that it will be an improvement over a display without local dimming as you simply have more flexibility