Well Paddy, you are probably correct, it is more a hub, with connections for USB, SD cards, HDMI and a USB C or
Thunderbolt port. But I've pretty much called anything I have to plug into a computer to connect with a port that doesn't exist on the computer a dongle for a while now, but you're right, calling it a hub would have been a little more clear. So it's about 6 years old. The strange thing is that the little green light that indicates it's powered up from the Thunderbolt port is on and I still have to disconnect and then reconnect to get the mouse recognized. This didn't happen in Big Sur. This was one of the first "hubs" available when the Thunderbolt (USB-C) MBP's came out and everyone was scrambling for connectivity solutions.
I use a 27 inch 4K UHD monitor because, like you, I like the real estate available for multiple windows, and 4K resolution is native to the Thunderbolt 3 ports on the MBP. I like using a mouse because I have to go back and forth with my PC for music applications, and it's just easier to use for me as I've gotten used to left and right clicking over time.
Guess I should think about being in 2022 and look into gettiing a Bluetooth mouse...