The user('s) to whom "view only site role" permission assigned is able to upload document

Issue

Logged in as a user to whom "view-only site role" assigned. The add "+" button is available to the user to upload the document.

Go to the site [Ex: Site1], navigate to Content / Document and media
On the upper right of the Document and media, click on the 3 dots ellipsis button
Select the "Home Folder Permissions" option. In this, check the Site Member role privileges and deselect the permission you are not looking for.
For example: uncheck the "Add Shortcut", "Add Document", "Add Folder", "Add Metadata Set" options.
Note: Please make sure that you have unchecked the "Add Shortcut" option
Save the configuration.
With the above configuration, the "+" button is not available to the user to whom the "view-only site role" assigned. And the user to whom assigned as "site owner role" is able to add the document by clicking the plus icon.

Reference:

Before configuring the suggested steps:

Configuration changes

After updating the configurations:

Note: Please find the attachment for the video demonstartion