You're lucky, for you the choice is actually easy - go for the QN85A you mentioned. The reasons are straightforward: it will be superior to OLED in your room conditions & its weakness related to local dimming in game mode are not relevant for your use case, finally size itself is always a bigger positive point over straight image quality once the TV is already a decent FALD. Not to mention it's a great TV and its inorganic nature as opposed to OLED means it will last you many more years and with kids watching it too burn in is almost guaranteed; wouldn't that be a waste, to spend all this money and have to buy a new TV in just a few years!
8K is not going to be relevant for the next 10 years as far as video content is concerned, and even for gaming it will be a very mixed affair mostly reserved for ultra enthusiast PC setups. As for 120hz, it's not very important for consoles but a nice plus. HDMI 2.1 is not very important outside of gaming, only exception being eARC for a nice surround sound setup. Overall nothing to worry about.
8K is not going to be relevant for the next 10 years as far as video content is concerned, and even for gaming it will be a very mixed affair mostly reserved for ultra enthusiast PC setups. As for 120hz, it's not very important for consoles but a nice plus. HDMI 2.1 is not very important outside of gaming, only exception being eARC for a nice surround sound setup. Overall nothing to worry about.