You can create an anonymous user and grant that user access to view the parts of Kibana that you need to show.
You will also need a proxy endpoint that attaches the anonymous user's credentials to the headers of requests, via Basic authorization. See Auto-authenticating to iframe-embedded Kibana dashboard - #4 by tsullivan
When embedding the iFrame code, the address to Kibana should be the address to the proxy endpoint.
Then when your coworkers visit the web tool that has Kibana embedded, the requests go through the proxy instead of directly to the Kibana server. The proxy bypasses interactive logins by automatically authenticating each request as the anonymous user.