voice or video calls using google talk in messages app Mac
If I'm understanding your question correctly, it seems like you're trying to use Google chat to initiate a call.   Google Chat/Hangouts/Meet has undergone a lot of changes in the last few months.  One of them is definitely which of those apps can make outbound calls.   As far as I know and currently experience, the only way I can make outbound calls from my macbook (I'm running Catalina though) is going directly to google voice in Chrome (https://voice.google.com)