Slack has options to communicate:
- that you're away
- that you're on a call or in a meeting etc.
- to pause notifications for an hour or whatever
- to star the most relevant channels
- to mute less-relevant channels
- to leave irrelevant channels
- to sideline conversations into threads
All of that is just Slack itself, in addition to things like putting meetings and vacations and other appointments on the shared team calendar. Some people where I work book meetings with themselves to guarantee focused distraction-free time. That's completely valid.
Part of being a professional is setting boundaries, communicating them, setting the expectations that the rest of your team will do the same, and of course, respecting those boundaries.
That includes not calling or pestering people that are on vacation. Which also requires that you don't "check in" while you're on vacation, because if you do, then other people will feel like they're expected to as well.
Set and communicate your boundaries, and in a team that respects each other, it shouldn't be a problem.