You can block ads on the NVIDIA shield launcher using Pihole of adguard DNS. Just need to go into settings for your wifi network on your shield, change dns1 and dns2, then reset the home app. It won’t be able to download new ads, so the banner on the home page will stay the default ad for several of Google’s own apps like play store and YouTube or whatever.

I too was not able to find a third party launcher that looked as nice as the original.