Being doing some reading on the very little we know about DLSS 3 and frame generation… I checked all Nvidia developer websites and no traces of any SDK yet. But I kept digging a little bit.
So apparently “DLSSG” is sort of the terminology used to refer to DLSS with frame generation, and you can see 2 sets of DLSS DLLs (lol) in the MSFS game folder for SU11. One DLL is the plain DLSS SDK (nvngx_dlss.dll) and the other one is the Streamline SDK wrapper (sl.dlss.dll). They both have a “G” variant: nvngx_dlssg.dll and sl.dlss_g.dll which would be the frame generation variants.
Of course it’s not a simple “replace the DLL” scenario 
the Streamline DLL is showing a bunch of extra logic for querying and presenting the interpolated frames (things named sl.dlssg.present.{real|interpolated} and all kinds of other cute strings pointing at additional functions and/or signals), which obviously the game would needs to implement.
But that takes me to the interesting part: the UserOpt.cfg file has a DLSSG on/off value that has already been established to be for 2D monitor, but it also has a DLSSGVR on/off, presumably for VR.
Has anybody with a 4090 tried to set this DLSSGVR to 1 and see if thing blow up in VR ? I’m surprised given the amount of tweakers on the forum that it hasn’t been brought up yet.
(to be honest, I highly doubt this setting would actually work, but if it’s there… who knows ?)
Edit: I forgot to mention, but it looks like Frame generation might be DX12 only? So be sure to try while DX12 is selected!