Much as I usually loathe solving human problems with tech solutions, this may be an appropriate time to suggest such a path.
I hated Slack(*)... until I was forced to use it regularly in some organizations in which I participate. It acts like a Skype that's fine tuned to organizational use with easy creation of ad hoc subgroups and the ability for participants to come and go at their own pace. Furthermore, real time chat now is great for diverse time zones and handles threads better than email. When properly used, chats can be where the preparatory work is done, leaving calls for decision making and when diversity of feedback is more important than focus.
- Evan
(*) while I have a Slack account for some orgs, my day job uses an open source Slack workalike called Mattermost. Other options such as Telegram and Microsoft Teams also exist. What I mean is that I'm suggesting more use of an organizational chat system but am not trying to push any one version or vendor.