I have essentially the same hardware as the OP and with the ICON A5 in a mountainous region of western Montana in the U.S., I get almost exclusively Limited by GPU at 40 fps. Here are the GPS coordinates of the region I’m flying if anyone wants to see if they can go to Limited by GPU. I am using the second set of graphics settings recommended by Spazzy, which seem to be a mix of ultra and high settings. Other than that, I’m preferring background services, running High Performance Dell power options (Windows cooling policy from “passive” to “active” under advanced Power Options settings, too). Optimal settings for Flight Simulator - Nvidia
Upper Holter Lake/Mann Gulch Region: 46°52’44.1"N 111°54’47.6"W