I had issues with Coso Cloud also.

I found Zoom has an LTI integration called 'LTI Pro by Zoom'. It works with moodle and a few other platforms.

Here is the link to get started if you want to check it out.
https://zoomappdocs.docs.stoplight.io/lti-pro-v2/welcome/getting-started
https://zoomappdocs.docs.stoplight.io/lti-pro-v2/guides/moodle

I followed the install and it was great.
I did customize some of the settings for my specific needs.

It can also be customized for teachers and other moodle roles. 

 

***Note: It launches into a separate browser when your website isn't configured as an approved domain)***

Click on 'Configuring LTI Pro on left hand side of instructions menu bar)

I have attached what the browser launch looks like within moodle.

When you carry out the install as mentioned in the above 2 links, you will be able to schedule zoom calls inside of this browser.

When you do so, it will add it into the students calendar (because you created the token). 

**If you create a meeting from Zoom directly, and not from the moodle browser, it will not show up in their calendar.**

Hope this helps!