I would go back and check all the fuses in the other fuse boxes with a multi meter before you start looking elsewhere.
I would also check the specific relays.
There are a few common fuses in there, so pay particular attention to those.
How did you get on with the CPS?
I will take that as a no then.
It is within the fuseable link.
It is the only fuse on its own.
The other fuses within the link are all in a row as per your image.
And remember and check your CPS.
The general rule of thumb is to avoid Nissan dealerships.
Also. most Nissan dealerships body swerve JDM imports.
There is a guy about an hour along the coast from you who may be prepared to help, however you would have to get the car to him and I am not sure if this is an option due to the distancing rules that are in place at the minute.
Check your CPS (crank position sensor)
However to be perfectly honest it could be numerous things causing this issue.
Might be a plan to get someone who knows there way around a 350Z to have a look.
Can you post up a picture of the fuseable link showing all the fuses.
Where are you based?
When fitted the ring looks like it is part of the exhaust and be easily missed by the uninformed.
However the ring can be swopped for a standard gasket.