Dsmr integration - water utility meter - unit-of-measurement missing?

Hello,

I’m using the dsmr integration for a long time for electricity. I just got a digital meter for water and can see value appearing. I see that the sensor doesn’t have a unit-of-measurement (m³). I tried to add this via developer tools but it get overwritten.
Can this be adjusted?
(i suppose I can create a helper as a workaround but would prefer to avoid this.

Thanks for the help