It's not AMD sponsored, it features Nvidia tech (Low latency + boost + DLSS) and AMD tech (CAS + FSR 1/2.). It's not sponsored by either company.
I can tell in that video that you had FSR enabled (or DLSS) without even looking at your settings as there are horrible outlines around the loot boxes and item pickups.
Turn that filth off, whichever tech it is. Using image reconstruction in COD/Warzone is Haram.
Also, that map you are running there (Ashika Island) is different to Al Mazrah and much less demanding on the system. I actually get higher FPS on the new map, Vondel, which has just been added in Season 4, than I did on Ashika Island with the 4090.
That map (Ashika Island) is still available to play. So if you want a true comparison, run that map again and compare.
On my setup, performance has not really changed much on Ashika Island from Season 3.
What memory, FCLK and curve optimiser settings are you running? Are they tuned? If not, you'll get less performance than me.