This is so silly. Again this is the very first area in the game. Use your brain. You cant get to 60 fps locked because you added an expensive upscaling solution, MORE RT effects, even after reducing the base resolution to just 900p. Instead of the variable 864p-1152p. What should this tell you? Take out the extra RT effects, remove the expensive reconstruction solution and just stick with what you have. This way you can use more than just the extra 12% GPU to get a locked 60 fps. And at that point the rest would automatically, literally automatically go towards rendering at a higher resolution. So dumb.
When will devs realize that PSSR has a cost not just on the GPU but also vram bandwidth AND vram size. Just keep using TSR which is perfectly fine at higher resolutions. The quality mode runs at 1620p on the unpatched disc version which should be better than 4k fsr quality. Just use that.