So from what I can tell.
1080p
6900XT > 3090 in Raster
1440p
6900XT > 3090 in Raster
4k
3090 > 6900XT in Raster. Closer to a 3080
Potato Ray Tracing
Super Potato when you enable DLSS
Still, AMD taking the people crown at any resolution is quite an achievement.
PC Specs: CPU: 7800X3D || GPU: Strix 4090 || RAM: 32GB DDR5 6000 || Main SSD: WD 2TB SN850