Sorry to hear about your trouble. Hopefully, someone with your hardware setup will chime in. As you know, these configurations are unsupported for use with After Effects.
Where are you looking to have AE support that card?
AE uses the GPU very differently for different functions and often it'll say unsupported for one thing that doesn't matter, but it works everywhere else. (Also keep in mind that AE doesn't use the GPU for very much.)
If you're looking in the ray-traced renderer settings, can you tick the "use unsupported cards" option?
Sorry for this issue related to your unsupported hardware. Did you ever find a solution? Please let us know if you have or if you still need help.
one way to let AE recognize the Nvidia Card is change the bios setting to 【PCIe first】
then the system would make AE notice the card and use the GPU resources.