Impossible with 300+ people in the org, and the expectation that everyone is available during work hours.
It's best to assume that not every workplace functions in a way compatible with this universal "let's turn off Slack and only check it once an hour" scenario. Also, these decisions cannot be made on an individual basis -- that's the best way to get fired -- but everyone else must be on board, at least your immediate peers. If you're not their boss, and they don't see the benefit, this will gain no traction.
The reality is that no, not everyone can remove Slack notifications and only check it once an hour or whatever.
No, I cannot "try it", it goes against official company policy. I will not risk my job on random advice from people working in a different country and for a different company.
Is it so hard to accept that "universal" advice is seldom universal, and that your circumstances may not apply to everyone?
It's best to assume that not every workplace functions in a way compatible with this universal "let's turn off Slack and only check it once an hour" scenario. Also, these decisions cannot be made on an individual basis -- that's the best way to get fired -- but everyone else must be on board, at least your immediate peers. If you're not their boss, and they don't see the benefit, this will gain no traction.
The reality is that no, not everyone can remove Slack notifications and only check it once an hour or whatever.