Hi,
Option 1: If you want default flow to use SSO without a click, then indeed change the script to set the cookie to /oauth/v2/login. You can use the 'manual' login (for as administator) by navigating to login.html yourself.
Option 2: If you want the users to click the button 'Login with SSO', you can keep the script to set the cookie to login.html and just place a button which redirects to /oauth/v2/login
Good luck!
__
Option 1:
Change index.html part to:
<script>
document.cookie = "originURI=/oauth/v2/login" + (window.location.protocol === "https:" ? ";SameSite=None;Secure" : "");
</script>
Option 2:
Add this to login.html:
<button id="ssoButton" href="/oauth/v2/login" class="btn btn-primary">Login with SSO</button>