Notebookcheck benchmarked the RX 6800 at 350 FPS in 1080p low and 107 FPS in 1440p epic (https://www.notebookcheck.net/The-Finals-review-Laptop-and-desktop-benchmarks.785549.0.html). Based on that, I'd expect better performance at 1440p low. This might be an issue with your hardware / configuration or with the driver/Linux. Are you getting the expected performance in other games?
I also second checking GPU utilization and temps with Mangohud.
Notebookcheck benchmarked the RX 6800 at 350 FPS in 1080p low and 107 FPS in 1440p epic (https://www.notebookcheck.net/The-Finals-review-Laptop-and-desktop-benchmarks.785549.0.html). Based on that, I'd expect better performance at 1440p low. This might be an issue with your hardware / configuration or with the driver/Linux. Are you getting the expected performance in other games?
I also second checking GPU utilization and temps with Mangohud.