I'm not a lawyer, just a coder. I was under the impression, that offering a network service is also defined as 'distribution': https://choosealicense.com/licenses/eupl-1.2/

I guess under (1) the "providing access to its essential functionalities" part is relevant: "‘Distribution’ or ‘Communication’: any act of selling, giving, lending, renting, distributing, communicating, transmitting, or otherwise making available, online or offline, copies of the Work or providing access to its essential functionalities at the disposal of any other natural or legal person."