There is a workaround will fulfill your requirement to some extent. Go SharePoint Admin Center(new)>Policies>Sharing>Advanced settings for external Sharing. Do not choose "Allow guest users to share items they don't own" The items they own means the items guest users have full control on.
The share button will still be there, but the guest users will not be able to use the people picker. In other words they cannot search for users. And they cannot grant access to the file to any other user. The share button only allow the guest user to copy a link to the file. And the link is effective only for users who already has access to the file .