This is deathloop in native 4k:
https://www.pcgameshardware.de/screenshots/original/2022/03/Deathloop_4K-native-pcgh.png
This is deathloop (same shot) in FSR2 quality:
https://www.pcgameshardware.de/screenshots/original/2022/03/Deathloop_FSR-2.0_Quality_4K-pcgh.png
Open up both side by side, and you notice how minor the differnces really are.
While one is basically twice the performance of the other.