What you are calling a "start menu" is more often referred to as an application launcher.
Specifically, you are currently using the default application launcher for KDE which is the Kickoff application launcher.
I'm not sure that you can easily make changes to the size of the Kickoff application launcher, but you can just use a different launcher that better suits your needs.
Right click on your current launcher and select Show Alternatives...
Next, choose the launcher that you want to use.
I would suggest using the Kicker launcher (also called "Application Menu"). Kicker has a much smaller footprint than Kickoff (which is non-descriptively called "Application Launcher")
hi in the newest version of Kubuntu 22.04 this is possible by hovering over the edge of the launcher menu and then pressing alt + right button on the mouse. This allows you to resize
What you are calling a "start menu" is more often referred to as an application launcher.
Specifically, you are currently using the default application launcher for KDE which is the Kickoff application launcher.
I'm not sure that you can easily make changes to the size of the Kickoff application launcher, but you can just use a different launcher that better suits your needs.
Here's a list of alternative "start menu" style application launchers for KDE Plasma.
To change the launcher:
Right click on your current launcher and select
Show Alternatives...Next, choose the launcher that you want to use.
I would suggest using the Kicker launcher (also called "Application Menu"). Kicker has a much smaller footprint than Kickoff (which is non-descriptively called "Application Launcher")
hi in the newest version of Kubuntu 22.04 this is possible by hovering over the edge of the launcher menu and then pressing alt + right button on the mouse. This allows you to resize