This is a known bug in Ubuntu 22.04. In essence, there was a change in sudo made to patch a security vulnerability, and it also inconveniently threw a wrench in the words of kdesu at the same time. The full report is here, if you're interested: https://bugs.launchpad.net/ubuntu/+source/ubuntustudio-default-settings/+bug/1965439 The developers are actively working to solve the problem.

Currently, there's two workarounds for this.

1. Run the needed commands in a terminal with sudo. This is probably the best option until the bug gets ironed out.


2. If you absolutely must have kdesu working normally, you can open the sudoers configuration file by doing sudo nano /etc/sudoers. Then comment out the line that says use_pty in the file, save your changes, and exit. Note that this will open a security hole in your system, the details of which are here: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2005-4890 It may also mess with stuff if sudo gets updated in the future. As a result, this is not the method I would recommend, but if you're determined to do it this way, here you go.

EDIT: This bug has has a fix released in the latest development release of Kubuntu, by disabling the use_pty option in /etc/sudoers. Having talked to the developers on IRC, I know that they considered the security implications of this before doing it. As a result, I still don't recommend option 2 because of the potential for upgrade problems involving sudo, but I no longer think the security concerns of option 2 are a problem.