hi all,
i managed to make the changes, i had two mistakes:
i had to clear the kimai cache via terminal (it is in the kimai docs)
https://www.kimai.org/documentation/configurations.html
when trying to clear, so the effects take place, i got an error. apparently you cannot use tabs as indentation, so my local.yaml was not readable anyway
after using spaces and clearing successfully the cache, every worked
thanks for the help!