as you didn’t ask a clear question I try to rephrase
Nextcloud docs:
It is highly recommended to restrict WOPI requests to the IP addresses of the Collabora servers that are expected to request files from the Nextcloud installation. This can be done by setting the
Allow list for WOPI requestsoption from the Office admin settings.Similarly, it is advised to configure Collabora’s WOPI host configuration to only serve IPs from expected hosts.
state you should restrict WOPI to known host using wopi_allowlist and refer to Collabora’s WOPI host configuration to adjust security on the COOL/CODE side. where do you struggle or what is unclear?
please review the Collabora integration guide to understand the WOPI protocol and the integration