The browser version of Zoom seems to require a free account be created, and it was audio only in Chromium, I could not get it to use my camera. Zoom refused to work in Firefox.
Jitsi and Google Meet seem to work in both browsers, without requiring me to log in.
You can join Zoom meetings on your browser without creating an account. It's a bit off the beaten path:
1. Go to zoom.com
2. Click "Join a meeting"
3. Enter meeting id and click Join
4. Ignore the automatic app download
5. Go back
6. Click "Join a meeting" again
7. Enter meeting id and click Join again
8. Ignore the app download again
9. Click at "If nothing prompts, click here"
10. Click "Join from your browser"
11. Agree to terms of service
12. Enter password and name, click Join
It's improved a bit, and actually works fine in Firefox Nightly right now, but you have to craft the web client URL directly. The UI will try its very best to make you download the client.
Seen somewhere else: when you get to the web page that launches the app, don't allow that launch, hit (IIRC) "Retry", still don't allow it, and the page should say "Having trouble?" offer a link to the web version.
I've joined plenty of Zoom meetings without creating an account. Are you sure it wasn't just asking you to enter your name and email in the page so people on the call would know who you are when you joined?
Jitsi and Google Meet seem to work in both browsers, without requiring me to log in.