Hi @Fanny JACQUET ,
Per my understanding, you could try to the built-in feature: Audit log reports.
You can use the audit log reports provided with SharePoint to view the data in the audit logs for a site collection. You can sort, filter, and analyze this data to determine who has done what with sites, lists, libraries, content types, list items, and library files in the site collection.
Go to Site settings->Site Collection Administration->audit log reports->click “Run a custom report”->set the save location, and and restrict the report to the library, and set the date range.
And do some settings as you want:
In the exported data, filter out the library you want.
Any reports available on Document Library usage
SharePoint metric for Document library : SharePoint Online
Go to the M365 Admin center>Complicance>Audit, select the library or file and user,time to export the data:
To go to M365 admin center, you could first go to https://YourTanentName-admin.sharepoint.com,then click:
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