I have the exact same issue with RDP_SCALE breaking the xfreerdp command.

Here's a quick script that you can use to implement the scaling automatically. You need to link this to /usr/bin/ and move the actual xfreerdp application somewhere else that isn't on you device path (like your home directory), and provide the script with the device path of the original xfreerdp application. Afterwards all calls to "xfreerdp" will run the script instead and pass all arguments along with the script's set argument for /scale-desktop:125. You can change the value on the scale-desktop to whatever percentage you want or change the arguments passed in entirely if you want some other default arguments passed in.

#!/bin/bash
[INSERT PATH TO xfreerdp APPLICATION HERE MUST NOT BE "/usr/bin)"] /xfreerdp "${@:1}" /scale-desktop:125

#!/bin/bash
[INSERT PATH TO xfreerdp APPLICATION HERE MUST NOT BE "/usr/bin)"] /xfreerdp "${@:1}" /scale-desktop:125

Hey I've tried to incorporate that into the actual project. I don't really work with bash scripts (my first pull request) so please can you double check the commit I've just added if possible?

#!/bin/bash
[INSERT PATH TO xfreerdp APPLICATION HERE MUST NOT BE "/usr/bin)"] /xfreerdp "${@:1}" /scale-desktop:125

Hey I've tried to incorporate that into the actual project. I don't really work with bash scripts (my first pull request) so please can you double check the commit I've just added if possible?

Luckily I've discovered the solution - someone has already done the work but the fix hasn't really been documented.

git clone https://github.com/adil192/winapps.git
bin/winapps check
./installer.sh

The file located in ~/.config/winapps/winapps.conf should have RDP_SCALE=125 and then all works.

Luckily I've discovered the solution - someone has already done the work but the fix hasn't really been documented.
git clone https://github.com/adil192/winapps.git

Yep that's my fork, glad you found it helpful. What issues did you have with the way it's documented?
From https://github.com/adil192/winapps#step-3-creating-your-winapps-configuration-file:

You will need to create a ~/.config/winapps/winapps.conf configuration file with the following information in it:

RDP_USER="MyWindowsUser"
RDP_PASS="MyWindowsPassword"
#RDP_DOMAIN="MYDOMAIN"
#RDP_IP="192.168.123.111"
#RDP_SCALE=100
#RDP_DEVICE_SCALE=100 # can only be 100|140|180
#RDP_FLAGS=""
#MULTIMON="true"
#DEBUG="true"

The username and password should be a full user account and password, such as the one created when setting up Windows or a domain user. It cannot be a user/PIN combination as those are not valid for RDP access.

Options:

• ...
• On high-resolution (UHD) displays, you can set RDP_SCALE to the scale you would like. RDP_DEVICE_SCALE is automatically set depending on your RDP_SCALE, but you can manually specify one of [100|140|180] if you wish.

Sorry, posted in the wrong thread - my mistake