OK pydio has reached EOL already 2020, see https://github.com/MichaIng/DietPi/issues/3469
There is also already a topic about this:
https://dietpi.com/forum/t/pydio-8-php-desktop-client-for-linux/16774
Here is also a instruction how to insall pydio cells on a RPi:
https://pydio.com/en/docs/kb/deployment/install-cells-raspberry