I've started keeping my slack status off permanently in working hours. It discourages people from contacting me, but I imagine the effect will wear off with time, as people catch on. The bigger picture takeaway is Slack status is not synonymous with me doing work that delivers company value (eg: doesn't mean I'm afk gaming or whatever).

The expectation of 'always on' is draining. I withdrew from social media for this reason, and now I'm applying that lens to professional communication software, in an effort to enforce barriers a bit better.