Low FPS - Limited by RdrThread?

Im struggling with low FPS but my GPU and CPU dont seem to being anywhere near fully utilised.

Im at 10-15 FPS, but NZXTcam reports my CPU at 20% and my GPU only 7%, so I cant understand why.

The frame rate monitor keeps telling me Im limited by RdrThread, any suggestions what is causing the issue and how to fix it?

Ive tried using low settings, and optimal settings via nVidia experience, but its still the same.

Im running an intel i9 9900K and RTX2080Ti with the latest drivers, so Im sure I should be getting better than this, its pretty much unplayable.!

Also, looking at the task manager, it shows GPU engine as GPU 0 - Copy, whereas other programs such as Chrome are using GPU 0 - 3D - I think this might be the issu, but I have no idea how to change it?

I am not a super expert on computers, but trust me – I have an i9-9900k, 32gb RAM, RTX 3080, SSD, etc.
I’ve never struggled with FPS until this last patch… and then a stranger provided me these tips and I followed each one and now I’m back to my normal FPS.

Performance drop 15-20% after update 3 - Bugs & Issues / Performance, Graphics & CTDs - Microsoft Flight Simulator Forums

The FPS counter is broken. It won’t go below 10 FPS. It looks like you’re getting about 5.4 FPS. Not sure why though.

In another thread it has been found that spikes and drops have been caused by Developer Mode. Dev Mode is an extension of the SDK. We know the SDK has issues. Try a different monitor and shut down developer mode. For a quick check win key + G will bring up the xbox screen and will show your FPS.

I may have wrong but be sure the RTX2080TI is the one you are using, and not the integrated GPU from the CPU. Check in NVidia Control panel and set power to maximum, and double-check in Windows settings->Game Mode->Graphics settings, and add Flight Simulator here with Max performance settings.