For a 10700K that sounds normal, especially if you’re flying around a handcrafted airport with complex airliners and lots of AI traffic. Be advised that Terrain LOD 200 matches the Ultra preset, while the High-End preset sets it to 100. I would recommend experimenting with a lower value such as 150. When you are flying over smaller cities without photogrammetry and large airports, you should be able to push it to 300 or higher and still get good performance.
It sounds like your GPU is exhibiting coil whine in high-load conditions. If it goes away in the menus and your framerate is capped, the GPU is consuming less power in these conditions. If you haven’t overclocked, I would recommend leaving the GPU as it is because the whine isn’t harmful.
If it is the noise itself that bothers you, undervolting is not very difficult and not dangerous at all, but it can be time-consuming because it requires lots of stability testing. There are several tutorials on YouTube if you’d like to give it a try.
That looks normal. When flying very low over photogrammetry at high speeds, the simulator is constantly paging in high-quality terrain, and the amount of draw calls goes up since the scenery tiles become smaller at higher levels of detail. A lower Terrain LOD value or a better CPU can help, but some stuttering should always be expected when flying this low and constantly panning the camera.