Chat widget - open upon page load on desktop only

We want the chat to open automatically upon page load on desktop (not on mobile) when agents are online. When agents are offline, the offline form should be served, and we do not want this to open automatically on mobile or on desktop.

To enable this, we have added the following code in the home_page.hbs section on GUIDE:

<!-- Start of portakabinhelp Zendesk Widget script -->

<script id="ze-snippet" src=https://static.zdassets.com/ekr/snippet.js?key=a90d5e61-18e2-43d8-9c1d-116b224215e1> </script>

<!-- End of portakabinhelp Zendesk Widget script -->

<script type="text/javascript">

        zE('webWidget', 'open');

        </script>

However, this ‘open on load’ code appears to override the chat widget and present the Offline chat code by default, irrespective of their being agents online or not.

Zendesk advised this is not possible with the available tools but may be achievable using code customizations. Please can anyone advise / have you experienced the same issue?

Thanks,

Beth