I would be interested in a proper solution, but recently I have found a way to make custom icons for specific Konsole instances. Maybe you could use a similar approach.

I have made a copy of the program’s desktop file and placed it in /usr/local/share/applications/ with a slightly different name, and given it a new icon. Then I have made a new window rule, that sets this desktop file for windows that start with a title having a specific pattern, and made Konsole to start with that title using an undocumented command argument I have found on their bug tracker.
This is very hacky and I don’t like it, can’t wait until it breaks, but it’s all I have found.

An alternative way may be to make a symlink to Konsole and start it through this symlink, and somehow identify the window by the executable path… but window rules don’t support that. Maybe through some other way? KWin has a scripting API… hmmm…

But a problem you’ll probably have to deal with when setting the title is that the program can set it’s title any time, and at least some of them (including Konsole) routinely do that, in that case based on the selected tab’s title. There’s a setting to turn that off… but as I have experienced, it doesn’t do what I expect, if anything. Maybe by listening to title changes you can force your will, if that is possible.