Ah, I remember trying out Tawk.to on Glide… and then they did not allow it to be embedded
And I wanted a Google Map and cool stuff for a project… no embed 
I found a cool booking system for my corona test app… but their widgets used javascript iframes… so no luck again.
A tragedy.
Or… is it?
A little lateral thinking is needed (and I hinted at this in an earlier post) - and @PabloMFalero.
A web page. You can put whatever you want on it… such as a Google Map. Or an iFrame with Javascript.
And then you use a webview in your Glide app. And if needed, zap / integromat data back and forth to the app to help control the UX (such as visibility of buttons, etc).
The potential functionality of apps has gone up exponentially.
Now, I wonder if I can build in a countdown timer that will play music when the time is up… or … whatever I can think of!