How to implement DRM-like access to a specific file

I have develope a tool using a simple LibreOffice Calc, and would like to re-distribute upon payment of a fee. The problem is that the file can be shared easily. My idea was to upload it on a Nextcloud user and provide access to that file from the web via Nextcloud login.

Would this be an effective solution to implement a DRM-like behavior? What other solutions do I have to monetize from such an app? Probably Cals is not the best solution, but wanted something simple so that could be sold for a really small fee.