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I will tell you what I understood you are asking me and how to do it. If I understood something wrong please clarify and I will guide you.

You have a backup made every day using one backup profile only. You want to always keep the backup made the 1st day of every month — and I assume the backups of the past 31 days as well.

Go to the Configuration page for the backup profile where you want this to happen. Scroll down and find the Quote Management section. Set the following:

• Enable maximum backup age quotas: check this box
• Maximum backup age, in days: 31 (Select “Custom...” and type 31 in the box which appears next to the dropdown)
• Don't delete backups taken on this day of the month: 1

You also said that you want to mirror the retention settings to the backup archives you keep on OneDrive. Namely, that you keep the backup taken on the first day of every month forever and the backups of the past 31 days as well. In the same page and section set:

• Enable remote files quotas: check this box

Please read this documentation page https://www.akeeba.com/documentation/akeeba-backup-documentation/configuration.html#quota-management to understand how the Quota Management feature works and what the options I told you to use do. The key concepts are that quota management is applied 1. using the information the backup records in your database, NOT the number, size or name of the files you have on your web server or OneDrive; and 2. per backup profile (if you have more than one backup profile the quota management for each profile works independently from the other profiles).