My 2012 Samsung Galaxy Nexus I9250 phone is "no longer recognized" by my computer.

[Android Central Question]

I have an older Samsung Galaxy Nexus I9250 phone purchased in 2012.
The software updates stopped at Android version 4.2.1 a long time ago.
I have been able to download photos via USB from my phone onto my MacBook
Pro labtop for years. However since March 2018, this has no longer been possible.
My phone is chock full of photos taken taken in 2018 so I have no more memory.
I can't get the photos off my phone because my computer no longer recognizes
the phone when I plug it into it with a USB wire.
Troubleshooting shows the hardware USB port and USB wire are fine.
Not possible to download File Transfer Software as the phone is not recognized.
Also, File Transfer Software needs Android version 4.3 according to Samsung.
Bluetooth not an option as my computer does not recognize the phone.
Any idea how to update the Android software from 4.2.1 to 4.3 safely?
I have seen some youtube videos showing it is possible. I just need to
ensure to get the photos off the phone intact. I am told that the photos
from this phone may not transfer onto a new phone at this point.