Sharepoint visitor edit homepage enabled

Hi everyone,

I am having a hard time with a permission in a Sharepoint site.

We use Sharepoint online as our intranet and i took some time to build it. I created the site as part of a site collection. We use the standard permissiongroups (visitors, members, owners, inherited from the top level site).

The site is working ok and we created a testuser and put him in the visitor group. The user has acces to everything, but should have only read/view right. Not download and certainly not any edit rights. Unfortunatly whatever we try to get the edit rights off the home page, it just will not work. It is either acces denied or edit rights. In our organisation it is completely unwanted to have some employees being able to edit anything. They have acces, can read, view, comment etc, but not edit. I turned to Microsoft (docs), pages, communities, external sites etc, but no one seems to be able to help. As a last resort i tried to get the edit rights off the home page itself, but it is already view only. When i select the link for viewing only, even then the testuser (who has no rights anywhere and is connected to nothing) can edit my homepage. I really need to get this started, or i need to take it out of Sharepoint and somehow build a regular website. it would throw me back half year of work. Hass nybody any idea on how ik can do this?

Thanks in advance, i am little desperate here.