This is really a social problem, not a technical problem. The technology for instant communication exists and it isn't going to disappear. Your coworkers need to learn to give people space to do their job. Sorry that's scant comfort if that's what your workplace is like.
It's a product marketing problem, specially Slack's. They market it as an instant communication product, but then they put threading and other asynchronous type modalities into it.
I have no problem with instant chat apps. I can set myself as away and people know not to expect a response.
But in slack it's a group conversation with the expectation of instant response, because that's how they market it.
