There are 2x Internet connections + racks - one in a house closet rack, the other in the garage.
Garage rack has a NAS that mirrors storage of the closet rack.
Garage rack has one Raspberry Pi GPS for time services.
Closet rack has two (different) Raspberry Pi GPS for time services.
Looking at it that way, if you accept the 2x Internet connections each being independant and acting as cross backups in case of ??? then it's just the second GPS on the closet rack that's "extra".
That can likely be written up as a home experiment in messing about with a different Pi setup.
It's overkill .. but often these home setups are there to keep current on new technology and different ways of doing the same thing .. in that light it's not uncommon to have multiple ways of achieving the same end just to gain knowledge on the pros | cons of different approaches.
I get using one for NTP.
I guess a second for redundancy even though it is picking up the same satellites as the first.
And the rest?