I having the same problem as listed on the US board but I can only post on the Canadian board: https://us.community.samsung.com/t5/Tablets/Tab-S6-Keyboard-and-Microsoft-Remote-Desktop/td-p/887233
When using the Microsoft RD Client to remote desktop to a windows host, the trackpad right mouse button does not work. The right mouse button does work inside Dex desktop so it is not a mechical issue. Other threads have reported that some older firmwares had this fixed but it fails in new keyboard firmwares. Both a bluetooth mouse and USB mouse work perfectly.
I got the tab s6 and keyboard cover last week. I have updated both the tablet software and the keyboard firmware. Both updates reported they worked correctly.
What is the process to fix this. Without it I will have to return the samsung keyboard.
I just found out that this problem only occurs while using Dex. If Dex is turned off than the right click work normally in MS RD Client.