I have two nvme cards on my rig, one being 1tb the other 500gb plus 1tb ssd sata which holds my OS the 1tb nvme has msfs on it and the 500gb has miscellaneous and FSX on it
My findings are that load times are pretty much the same , but I don’t get stutters etc
Another thing is cooling, if you block your case with multiple ssd’s it will disrupt your from fan cooling
Alternatively get a 2tb ssd and have done with it
Depends on your set up but the difference between sata ssd and nvme imho is not massive, it’s better but not really noticeable to give you a wow factor
Just my 2 cents