After the install of the 757 and all of its variants, i went to go do my first flight only to find that my sim was running at an agregous 5FPS, this issue never happened before the 757 install but even a uninstall didnt fix the issue. My computer is more than powerful enough to run the 757. I run probably an addtional 15 addons that never caused an issue ranging from orbx, another company, another company, and the 767. But now my sim wont go above 5 FPS and i cant figure it out.
Ryzen 9 5900x
32 gb 3200 Trident Z Royal
RTX 3070TI FTW3 Ultra
Aorus Master X570

P3D V5.3

Not sure if this will be any help but I have experienced low frame rates at times and believe it is related to add-on airport scenery which may not be totally compatible with 5.3. I found various solutions - sometimes deactivating the scenery and / or  re-installing or finding a more compatible airport package. My specific problem occurred at KRSW over Orbx True Earth Florida. After re-installing KRSW my FPS changed from about 5 or less to 27 and about 23 with VR.