So after having read this I was trying to configure Konsole by editing my config files under

~/.local/share/konsole

and I couldn’t get my column width config to apply.

The problem was that I was configuring column width with the TerminalCols setting, but the correct setting is actually TerminalColumns, which was difficult to figure out! Not sure how I managed to get that wrong in the first place, but it’s fixed now.

My new Konsole dimension settings are:

TerminalColumns=100
TerminalRows=42