I got one of these and have been pretty happy with it:
https://www.amazon.com/dp/B09237LL5Q/ref=pe_386300_440135490_TE_simp_item_image
I work on a MacBook Air and apparently there is no second monitor that you can use with one of those, where you can do a touchscreen. That's really my only complaint - I'd like to be able to use it as a touchscreen.
But even when I hook up my iPad to my computer as a second monitor I can't use the touchscreen, so that's not a fault with the monitor, it's a limitation of my computer.
Anyway, the ViewSonic has been good for calls, editing docs, looking at spreadsheets. It's been really fine, and it's very lightweight, too.