I came across this article that covers clientless Skype and have exercised it successfully.
Here's how it works.
Go to https://www.skype.com/en/free-conference-call/ and click on "Create a free meeting".
Keep clicking until you get a response.
Then click on the little "copy" icon at the end of the URL.
Save that URL. It can be used over and over.
Share it with the people you want to participate.
It works on Windows 10 with Chrome and Edge (not Firefox) and on a smartphone with an installed Skype app.
The following is for Windows 10 with Chrome.
Click on the link you just created.
Click on "Cancel" and then "Join as guest".
Enter your name and click on "Join".
If you're the first in the meeting you may have to click on "Start call".
And then click on "Start call" to start the call.
This supports up to 50 concurrent users.
You shouldn't have to install anything or create an account.
You may get some prompts requesting permission to use the camera and microphone. Respond appropriately.
However, if you want to run your Windows Skype app, on the first screen click on "Open Skype". and login to your Windows Skype app.
Alternatively, if don't click on "Open Skype", you can click on "Sign in" and log into Skype with your Microsoft account using the web interface without an installed Skype app.
If you do this on a smartphone, it will try to launch a Skype app.
And it's free!