You have a culture problem, not a technology problem.
> It’s common in the software industry to blame the users. It’s the user’s fault. They don’t know how to use it. They’re using it wrong. They need to do this or do that. But the reality is that tools encourage specific behaviors. A product is a series of design decisions with a specific outcome in mind. Yes, you can use tools as they weren’t intended, but most people follow the patterns suggested by the design. And so in the end, if people are exhausted and feeling unable to keep up, it’s the tool’s fault, not the user’s fault. If the design leads to stress, it’s a bad design.
https://m.signalvnoise.com/is-group-chat-making-you-sweat-74...
So culturally most teams value communication, therefore you need notifications because communication is an inherently valuable good. But this is a tool for a business sector where the $$$ are generated by people in deep flow, and notifications disrupt flow. So there is a technological design failure of including a notification system but culturally not being allowed to say no to it.
For example, everyone hates the (non slack) IM system where I work because its a disruptive annoyance of little value, so we all complain much like op about the users using it wrong, when whats really wrong is the design and we don't have the strength to overrule the cultural value.