Andrea:

He keeps giving me the exact same error.
However, after the installation I had made a new login to
automatically configure the PATH.
- I brought the DeviceQuery folder from /opt to /home as recommended
by Arch wiki. Here I gave the make.
That creates the problem -- that is, you moved something.
So you can either make a copy to put it where it originally was.

OR if you key in the following first, you will get partial success that is usable (ignore the release error) and you will now be able to run deviceQuery.  This worked for gg on a test system just now.
 
export EXTRA_NVCCFLAGS=-I/usr/local/cuda/samples/common/inc/