Benefits of gfci and Afci redundancy in circuit
Nuisance tripping or false tripping is a real thing in both devices for different reasons. nuisance tripping of GFCI’s is well documented and there are also issues with AFCI’s where they can’t tell it’s a dimmer or speed control and trip.
The reason you don’t see studies on redundant devices is because they affect each other and some devices self test will trip other devices and getting them all reset can be impossible.
I once was called to a home the owner tried to do exactly what you mention after hours of trying to rewire and get them to reset he called me. I told him he could have each receptacle as a line fed and not use the load but still may have some false tripping and finding the tripped receptacle would be easier but there would be no redundancy.
At that point with each point protected individually protected there would be more chance of failure because Electronic devices (both AFCI &amp; GFCI) do fail.
So in his case he went back to 1 per circuit.
This is the reason you won’t find studies on redundant devices and although I have not read the mfg instructions lately they used to identify this in there documentation that came with the device.