c10le v Server 2019. Really confusing performance problem.

Hi.

I have a building with 50 or so archaic Wyse C10LE thin clients, currently connecting via RDP to 3 terminal servers, each running Windows Server 2008R2.  Firmware is 8.0_210. Configuration is stored in a central WNOS.INI file, and pulled down via FTP, as directed in DHCP. All works as expected. Network is 1Gb everywhere, and works fine.

I am looking at replacing the old Server 2008R2 RDP servers with new ones, which will run Server 2019, with some upgraded applications. I am having a problem with performance using the Wyse devices with the Server 2019 RDP host. The connection establishes as expected, however dragging windows around or scrolling is annoyingly lethargic. Move a browser window, release the mouse, and a couple of seconds later is moves. Works, but will seriously bother users.

Through a method of trying EVERYTHING, I have determined that if I clear the "Auto detect network" checkbox on the properties of the connection I am using, speed is fine. I am NOT disabling anything under "desktop experience", just clearing the "Auto detect network" checkbox. . The actual "Desktop experience" setting make negligible impact on performance, since the machines are on a fast LAN. It is just enabling the "Auto detect network" checkbox that seems to break things. I know this makes little sense, but it is what is happening!

All is fine provided this change is manually made at login, but that is not a fantastic solution for production. I have read a heap of documentation covering what can be configured in a WNOS.INI, as best I can determine, this is one setting that cannot be controlled in that manner.  I tried adding "LowBand=yes" and "Lowband=no", this seems to only alter the settings of the "Desktop experience" parameters IF  "Auto detect network" has been manually disabled.

Can anyone shed some light on this? Can the "Auto detect network" somehow be set in WNOS.INI?

Copy of WNOS.INI (PFS-TS07 is the Server 2019 box)

Autoload=2 ;
MaxVNCD=2 ;
VncPassword=Deprecated encrypt=no ;
SessionConfig=ALL Fullscreen=yes;
SessionConfig=RDP ForceSpan=yes;
VNCPrompt=no ;
Signon=0 ;
Reconnect=no;
Sessionconfig=all unmapusb=yes mapdisks=no;
TimeZone='GMT + 08:00' ManualOverride=yes
TimeServer=0.pool.ntp.org;
Dualhead=yes ManualOverride=yes Mainscreen=1 \ Orientation=hort Taskbar=mainscreen Align=Right MonitorAutoDetect=yes
#Not in use, remmed by Mal, 20-8-2015
#include=$mac.ini

CONNECT=RDP \
       Host=PFS-TS03.pfs.ad \
       Description="PFS-TS03" \
       Colors=true \
       Fullscreen=yes \
       Domainname=PFS \
       LocalCopy=no
CONNECT=RDP \
       Host=PFS-TS04.pfs.ad \
       Description="PFS-TS04" \
       Colors=true \
       Fullscreen=yes \
       Domainname=PFS \
       LocalCopy=no
CONNECT=RDP \
       Host=PFS-TS05.pfs.ad \
       Description="PFS-TS05" \
       Colors=true \
       Fullscreen=yes \
       Domainname=PFS \
       LocalCopy=no
CONNECT=RDP \
       Host=PFS-TS07.pfs.ad \
       Description="PFS-TS07" \
       Colors=true \
       Fullscreen=yes \
       Domainname=PFS \
       LocalCopy=no \
       LowBand=no