Not really the same, Nvidia already had fundamental GPU tech AMD didn't. AMD gets a whole lot of crap for over paying for ATI, yes they did but long term it was a great acquisition. IIRC Intel paid more for McAfee than AMD did for ATI.
That cooler already has all you need to connect the pump and fans to the ARGB port on your mobo
For more ARGB ports get the splitter you linked to or get a simple ARGB splitter cable. The board you linked to will work all it does is feed...
From what I've read this board has a very high failure rate something like 1 out of 5. Other X570 GigaByte boards have been flaky as well or outright die including one I had the Aorus Wifi it was okay at first except had a cold boot problem. After a few days the board wouldn't post at all. RMA'd...
So you're saying if a Polaris equipped card is reviewed in the proper context it could also get a Gold award. But by all means expect a tiny GPU to compete with the likes of the 1080 makes perfect sense because 14nm and 16nm.
How is it on a tech forum some of you don't know the difference between an architecture and a specific SKU? "Polaris can't beat Pascal" a tiny bit more granularity is needed for that to have any meaning.