Dear Ricardo,
Good day! Thanks for posting in the community. We are happy to help you.
For your query, you can unpublish/delete the major version file 1.0. It will only make this file lost the major version 1.0, and you still have other versions.
According to the screenshot, I assume version 1.21 is the current version. If you still keep 1.0 as the published major version, when you delete all versions, the current published major version will still be 1.0, and only version 1.0 and 1.21 will be left. If you have unpublished 1.0, then delete all versions, only version 1.21 will be left and there is no major version.
We look forward to your response. Thanks for your cooperation.
Sincerely,
George | Microsoft Community Moderator