You misunderstood how this works. To run concurrent meetings, you'll need multiple devices or co-host/co-hosts to manage the second meeting. This is how Zoom and Google, which you referred to, work (you need a co-host).
You cannot be in two meetings or webinars simultaneously. If you have a co-host, you can schedule concurrent meetings, assign them as the moderator, and they can start and moderate the meeting on your behalf, just as Zoom works. If you need to run concurrent meetings, please add additional host(s).