You consistently push this fallacy that Nikon is falling behind in mirrorless. Yes both Nikon and Canon got a late start in mirrorless but both have made great advances. There are things There are things each brand does better. Pretty much all the issues with Nikon’s initial release have been fixed with firmware updates. Each company has recently released a new camera. Both Canon and Sony have gone more video centric, with Canon’s big feature being 8K video. It’s a camera with impressive specs but has also already had some serious issues. And really for most of us 8K is overkill. Unless you’re shooting professional video why would you shoot 8K. The files are huge and I wouldn’t want to process them without a professional video workstation. Really 4K is overkill for most people. Sony’s new entry is a real head scratcher, it’s basically a video camera. In 2020 and going forward nobody is gonna buy a 12mp camera for stills. Nikon took a different approach and went with an entry level FF camera that is geared to still photography. It’ll still do better video than most DSLR’s but it’s designed to get people that don’t want to drop $2000 plus on a new camera into mirrorless. Nikon developed the best and most flexible mount system that really opens up the door for advances in lens design and there’s even conjecture that it could support a medium format body someday.

Two items, First the Nikon mount is new to Nikon. The Canon RF mount is 1mm smaller that means 1/2mm on each side which is imperceptible. Thus it has no intrinsic superiority over other mounts. It is just 30 years late in growing up and catching up. Second Nikon is still struggling with AF speed on the Z cameras compared to the DPAF II now available that is demonstrably faster and more accurate.
That said Nikon has done well and is starting to catch up, they make a good solid general perform=ing product in the Z system currently and it will get better as time goes by.
But the mount by today's standards is pretty normal.