EDIT:
So according to this thread, this is a Google related change and not Nvidia?
In which case, similar to the banner issue from a previous update, you can get a different launcher (see comments for FLauncher) to avoid it
https://www.reddit.com/r/ShieldAndroidTV/comments/181vh4t/ads_at_full_screen/
I would never regret about my Nvidia Shield TV, in fact it is one of the best purchases I have ever done, I have one since 2018 or 2017 perhaps and that unit got busted and Nvidia replaced mine for free (they sent me a power adapter first, which didn’t help for my issue, for free too) even when it was outside of the warranty period, and they didn’t even replace it for another 2017 unit, they gave me the 2019 pro, perhaps for inventory reasons, (and a ruler as a gift lol) a very pro move if you ask me.
Now the 2019 unit is dated for sure, and the launcher with ads was a dirt move sure, that is why I downgraded the unit and debloated it, this is how my unit looks like now.
I mean I still appreciate they are still supporting hardware from 2015 in 2023.