"Of course I couldn’t use the same USB cable for both devices."
Trying to transfer pictures from my Doro phone via USB has always been a frustrating exercise. The little red light would flash to show it was getting power from the laptop's USB socket - but it wouldn't attach it as a storage device until you found the sweet spot angle of wobble at the phone end.
I had always used Doro supplied USB cable's from the two phones I own - just in case they were non-standard connections. So it looked like the phone's USB socket was in some way intermittent.
One day I couldn't find either of the Doro cables - and just happened to have a generic one to hand. Not only did it work - but the storage was recognised immediately. It appears that it has a slightly longer plug that makes a more rigid connection.