You know you can disable notifications right? That gives you the same peace of mind. If it's someone important you just tell them hey, I'm in the middle of x, I'll get back to you at y time. Most bosses respect healthy boundaries, and if they don't that's usually a red flag.

Not everything needs to be responded to right away, my mind was blown when I first saw an eisenhower matrix. I encourage you to check out this! https://www.google.com/search?q=eisenhower+matrix