In the office one person at a time can DOS attack my attention and everyone else can see I'm busy helping them. Slack is far worse, multiple coworkers are DDOS attacking me and 10 more unread messages pop up before I finish helping the first guy.
There are easy solutions to these problems. Put up an away message and silence notifications. Set office hours when you will respond to messages. Time box. Give estimated response times. Provide an escalation method for emergencies. Keep a weekly rotation for support requests.
All of this is well established in fully remote companies. But you can't expect to completely change the dynamic and expect it to work perfect with no changes.
Without sarcasm, I think a lot of people think this is what "important hallway conversations" and "collaboration and innovation" are. I also find it hugely disruptive, and it caters to people can mostly only communicate verbally.
People message me while I'm on zoom, I tell them I'm busy but I'll get to them in the order they reached out. It works just fine. I have a note on my computer I add their name to and once I get off zoom I check if I still need to reach out to anyone.