Maybe passenger side behind glove box next to TAU,I don't know. Let us know if you find it.
It doesn't use Canbus so you could disconnect it altogether.
Sorry, wrong info TAU is always on the right in a LHD or RHD, in your car it should be on driver side.
If you search for the part number K131-66DF0 (without revision number B) you get a result in this forum - and it says, that it is located near the TAU, like craz assumed. Source: Firmware update Japan to Europe - MZD
ok, guys. Now it became more interesting.
I have Japanese Mazda with installed with 70.00.367 EU and CarPlay/AndroidAuto box.
There was no blue GPS connector to CMU. I had also 0 GPS satellites and error B119F. Android Auto navigation didnt work (GPS is taken from car), CarPlay navigation worked (GPS is taken from Iphone).
I bought GPS antenna with GT5-1S connector on AliExpress and installed it to CMU.
The car now has GPS, AndroidAuto navigation works but still error B119F(1D)!!!
I've looked at DTC and it's CMU detecting a current draw of 31ma or more from the Aliexpress GPS antenna circuit. Contact vendor and ask if he knows how much current antenna draws.
If you still have concerns second hand GPS OEM antennas (2014-2018) are inexpensive and they are the same in all models but got different part numbers, check Poland Allegro or Ebay. Make sure it has Blue RF connector and long enough cable to reach where it's mounted, Green plug it's an extension.
First picture: Yes that's it but wire is very short.
Second pict: Empty port is not gyro antenna input, first blue plug and gray wire it's the antenna but also that plug won't fit CMU.
If you want to continue the search trace gray cable back, Mazda 3 GPS antenna it's mounted in dashboard close to windshield.
Antenna you've bought it's correct in frequency and voltage but the system would complain for not be in OEM specs but I think if current is not excessive CMU would handle.
If everything it's working and DTC wouldn't affect operation keep using it. Although I would recommend pull all plugs from the unused gyro unit.