I have dual monitors connected to my macbook pro via a dual display docking station. I am unable to view 1 monitor in portrait mode (vertical) and 1 monitor in standard (horizontal). The rotate screen option is not available in display settings but if I connect a monitor directly to my mac the option is available.
MacBook Pro 15″, macOS 10.15
Hello MikeMace and welcome to Apple Support Communities. It appears you are having some difficulty with a dual external monitor setup with a MacBook Pro.
It sounds like you have already isolated the behavior to the 3rd party dock. If this is a newer Mac with only USB-C connections, have you tried connecting each monitor to it's own port on the Mac? If you can do that and still have the ability to rotate, it would 100% isolate the issue to the dock.
Cheers.
Did you look in the sidecar setting
Dual monitor portrait mode (veritcal) and Standard mode (horizontal) via Docking station.
