The review scores are dependant on the price and the specs of the TV. The U7Q competes in price to budget end models that don't even have local dimming or more than around 300-350 nits peak brightness, so is much more favorable compared to them.
The U8Q on the other hand has specs that compare to higher end models. 1500 nits peak brightness is something only TVs like the Sony XH9505 and Samsung Q90T reach, and those TVs cost a bit more, 120hz panels are only found on higher end TVs too.
So the total review score doesn't mean a lower end TV with a better review is better than a higher end one with a worse review...and besides, a review score of 8/10 vs 7/10 is very close, and both TVs are recommended.
Part of the reason local dimming is scored down on the U8Q will be because it has a lot more brightness to hold in than the lower end U7Q, but its kind of a faux argument because the 700 nits of the U7Q doesn't cut it where HDR is concerned, so only the U8Q should be considered if someone wishes to use HDR on the TV.
As time goes on, other models from Samsung and Sony will come down a little in price and may become attractive propositions compared to the Hisense U8Q. At the moment though nothing comes close. But that is the market at this time of year, and why its a bad time to buy a TV at the moment. The price difference is representative of how much Japanese/Korean manufacturers hike there release pricing compared to Chinese ones.