How do I set Zoom as my meeting platform in Google Calendar?

Note that administrators are the ones who can set Zoom as the default meeting service on Google Calendar or turn off Meet as the default provider to allow users to choose their preferred meeting platform each time. As to answer your question, I've provided steps below on how to set Zoom as the default meeting platform on Google Calendar.

1. In the Google Admin console dashboard, go to Apps, then GSuite.
2. Click the three dots next to Google Meet.
3. Click Turn OFF for everyone.
4. Install Zoom for all users in the Google Marketplace, which can be found as Zoom for GSuite.
5. From the Google Admin console dashboard, go to Apps, then GSuite.
6. Click Calendar.
7. Click Sharing settings, then Video conferencing.
8. Check Automatically add video calls to events users create.
9. Click Save.

Sources:
https://support.zoom.us/hc/en-us/articles/360050650992-Setting-Zoom-as-your-default-with-Google-calendar

https://support.zoom.us/hc/en-us/articles/201974323-Using-the-Zoom-Chrome-Extension

HTH. Cheers.