I simply do not use google products beyond search and maps because I can't trust they'll be around without significant changes (gmail) or discontinuation.
Own the domain name, but let one of the big players handle deliverability for you.
I wish there was a modern protocol equivalent with authentication builtin.
Big wall of NOPE.
Also speaking of mobile apps, Fastmail actually supports push notifications for email in Apple Mail. I'm not aware of any other third party email provider that's ever done that (I believe Yahoo! has support for that but Apple did that themselves when the iPhone first came out).
Is there any other software that does this as well as Hangouts on Air does?
The feature that made Hangouts Live so good was that groups of people could instantly stream together from anywhere in the world, and the focus shifted to whoever was talking. It made multi-person casts incredibly simple and didn’t require having someone running OBS and managing the stream.
Sadly this more than doubles the price of the per user package and doesn't match on features.
The good news is (bad for retailers/providers) prices on old products never go up.
Discontinued August 1.
"The classic Hangouts On Air streaming experience is going away later in 2019. For quick streaming, try YouTube.com/webcam"