The user writes a message in a chat and can select additional recipients before sending.
Then DC sends each a separate email and displays these messages in the corresponding chats.
It is also possible to forward a message to multiple recipients at once.
It is not possible to forward a message to multiple recipients at once.
Groups and broadcast lists make it possible to send a message to multiple recipients.
By creating a group or broadcast list, messages can be sent to multiple recipients.
However, this approach is not ideal in every case.
Broadcast lists are not encrypted and create “gaps” in the normal chat history.
In many cases, users only want to send a message to several contacts once and not create a group or broadcast list specifically for this purpose.
If I understood it correctly, broadcast lists will be converted into channels in the future.
Therefore, the proposed features would make sense to replace the missing broadcast lists.
Forwarding to multiple recipients could be done by adding a multi selector to the selection screen.
In order to send a message to several contacts at once, DC could display a selection screen when a user holds down the send button or right-clicks on it.
Personally, I would prefer this solution.
However, this approach has the disadvantage that the feature is not immediately obvious to inexperienced users. So it might be better to display a button instead.
Maybe this would make the UI appear overloaded.
By the way, no messenger that I know of has such a feature.
Button in DC-iOS to show the selection screen for multiple recipients:
Selection screen for multiple recipients in DC-Desktop: