cannot uninstall video 1.4

Problem/Motivation

Hello.
I cannot unsinstall the video module. In /admin/modules/uninstall there is :
The field type video is used in the following fields : media.field_media_online_video, media.field_media_video
I dont find where those fields are declared, or used, where they do come from...
There has been no video content created on our site. We need to remove it because it introduces an issue preventing us to upgrade to D9. We've just migrated from media_entity to media, for upgrading from 8.9 to Drupal 9.
What can I do please ?

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes