Dariusz Breś (see his previous posts) upscaled one of his photos taken with the Nikon Z7II camera from 4,000px to 16,000px with the Topaz Labs Gigapixel AI software. The results are impressive - you can download the 16,000px photo from Flickr:
The latest Topaz Labs Gigapixel AI version 5.8 was recently released with several improvements and it is currently 20 off until February 18 (you can use coupon code RUMORS15 to get an additional 15% off):