RemoteApp on Windows Server 2019 lags heavily

My Setup

I do have to following RDS / RemoteApp setup:

• Windows Server 2019 hosting all RDS Roles (RD Web Access, RD Gateway, RD Licensing, RD Connection Broker and RD Session Host)
• Everything is configured and the access to remote apps via the RD Web Access website works well in general

My Issue

Working with the published remote apps lags massively while accessing it with certain clients. Trying to move an application, typing some input, maximizing or minimizing it is really slow. We're talking about a multi-second lag which makes working with these apps impossible.

Findings / Remarks

• It only lags on a few clients (3 out of 20+)
• All clients are running Windows 10 and are always on the newest patch / feature level
• Accessing the RD Session Host Server via RDP / Remote Desktop works on all clients without any issue. Therefore, network latency cannot be the issue
• All published remote apps are affected
• One of the clients works seamlessly as soon as an external HDMI Monitor is detached

Steps I did trying to solve this issue

• Verified the patch level of the server and all affected clients => OK
• Updated all graphic and display drivers on the affected clients => did not help

It does look like an issue on the clients side, not on the servers side or am I wrong?

Any idea what I'm missing here?

Solution 1:

Altering the mouse polling rate from the mouse default value of 500 reports per second to the system default value of 125 reports per second solved my issue.

tl/dr;

All of the three affected system had a gaming mouse attached (Logitec G400S) which uses a higher than usual mouse polling interval of 500 reports per second compared to the usual 125 reports per second, which caused the lag. To be able to alter the mouse polling rate, I had to install the Logitec Gaming Software on the affected systems. Another solution would be using another none-gaming mouse instead.