Mode

GOOD:
It will take 1h to really configure it, but after that the policy is set for all clients.
IOS, desktop works well, video is clear, sound is clear. Tested, works.
Nice UI, functional, have all the credentials to not go bust.

TO UPDATE:
Requires typing the password for each app open
Forces you to use software 2FA
We need a good roadmap like frill.co (come back to AppSumo) to add our recommendations

You have only 2 other alternatives:
Off the shelf chat app (self-host) like Matrix-Element / Custom-built chat app (self-host)
You have to update, maintain, custom code each, be responsible for failures... Security vs Privacy debate.
Why not have both? A matrix self-hosted for friends and Mode for work.
High reliability if you have both.

If you buy the deal, we'll have people invested and interested to make it better.
Only 1 question left. What's the team's response rate, willingness and technical capability to innovate on time?
Till now, customer service is on point, but we'll need the mentioned updates done.

If you want a working chat app with security this is it.