You likely have a select.dishwater_program entity or similar.
Use an entity state trigger on that select entity (rather than a device trigger), with a value likely similar to Eco50
But it is all guesswork. I have gone through the integration documentation and while refers to the need for key/option does not define what the entry is.
Push comes to shove we can go back to setting the timer manually when Home Assistant 2025.6 comes out.
Pity it has been pretty useful a shame it is end of lifed.
All the above basically means: turn on your dishawsher, reload the integration (or restart HA), log out of your Home Connect Developer account, then check the device page (or Developer Tools) for your dishwasher.
You should see something like a drop-down menu named “Active Program” there.