Add the prefix. The city name can be adjusted by the owner accordingly and the settlements status is more accurately shown.
Ex, I would change
"(township) New Berlyn City" as it currently shows to
"In the township of New Berlyn" and omit the “city” part from the name.
I don’t think the case of non-cities being listed as cities will be a problem very often because that is a huuuuuge prestige goal to reach.
Another option would be to let the owner toggle the name between “Landmark” names and “settlement names”. Ex a large mine would have landmark titles like point of interest, monumental, greater monument, landmark. This could accurately describe large solo builds that arent settlements.
Edit: no worries, New Berlyners. It will reach city status before this change can take effect.