Ah, I didn’t look at the video.
No, I doubt this is normal if it’s also in the stock A320. Even with high glass cockpit refresh rate I can reach high framerates, especially during climb/cruise when most of the view is a blue sky.
Do you have anything running in the background that might cause issues? Either by using CPU or by slowing down in another way. (I had that issue with Acronis True Image’s anti-ransomware protection, which costs me about 27 fps when enabled!)
Worth checking if you have any kind of antivirus/antimalware/anti-… except Windows Defender which should be fine.
If it feels worth the effort, try changing to 1440p and High settings, then start with the stock(!) A320 on ESSA RW26 with no traffic, no MP and clear skies and check your framerate there.
I tend to have about 75-80 fps while still on the runway, climbing to above 100 in the early climb (within a minute of takeoff). If your performance is way off that (like below 65 fps on the ground at 1440p High, or below say 85 climbing) even with the camera not moving, I’d say something is definitively wrong.