On Eglide, we currently use packages.sury.org for PHP packages, but no reference to that repository exists in rOPS.

Could we configure it?

See https://packages.sury.org/php/README.txt for the files to provision:

1. GPG key at /usr/share/keyrings/debsuryorg-archive-keyring.gpg
2. Repository to /etc/apt/sources.list.d/php.list