It’s actually commom for Chinese companies to sell the rights to re-brand their merchandise. Lucky for us because we know that it is the Kingwear KW88. Not everyone will know that.
Manufacturer keep rights to make a deal and spread their product with different company’s , as you know Kingwear and Finow manufacturer’s are not their own, they getting from different one.
Actually the board is used in many many different watches. The case is the only difference and its not exactly owned by anybody - they all copy each other over there anyway.
So far looking at the video of @SmartWatch_Ticks the only one that had a duplicate pcb was the ZblitZ/Z9/S99, but your probably right, they could be all based on default example schematics/pcb from the mtk processor.