In my opinion and experience there are very few issues that require you to actually respond immediately, I just find many teams don't understand this. Everyone thinks their specific issue is the highest priority thing going on, and I'd say product teams are especially bad about this. Asking for status updates all too often and interrupting developers days just for small things that could've been done at a scheduled time or just been an email.
Obviously this can somewhat depend on your role since your role may be something that tends to require immediate intervention. But I check Slack once every 30 min to an 1 hour or so and have no issues with my response times.
This means people can book meetings when people are free instead of being limited by the availability and preplanning of big enough rooms!
I've been on teams where we explicitly defined expected response times. 2 hours was the typical answer on teams where I've worked.
I've also been on teams that didn't define the expectation, but nobody I work with expects Slack to be real-time. The only time we respond quickly is when we have first asked, "Hey, let me know when you have a couple minutes to chat." And then I either stick around until they have time and quickly have the chat/huddle... or if they don't respond and I need to step away, I delete my message.
It sounds counter-intuitive but you can often build a better remote culture by being a little less responsive.