You can turn off the Hangouts links that Google automatically adds to your events.
See info below for both G Suite users (if your team's on G Suite), and also for personal Google accounts.
G Suite accounts
- If you're on a G Suite plan, this setting is changed by an admin. That's the person on your team who has access to this page: https://admin.google.com
- The admin clicks on this link, https://admin.google.com/AdminHomefral=1#AppDetails:service=Calendar&flyout=sharing
- In Video Calls, uncheck the box Automatically add video calls to events created by a user
Other Google accounts (not G Suite)
- Open Google Calendar
- Click cog in top right
- Select Settings
- Scroll down to Automatically add video calls to events that I create
- Deselect the box there.