Don't sweat it. Make sure your manager understands that your velocity is limited by colleagues treating asynchronous communication as synchronous. You'll either

Don't sweat it. Make sure your manager understands that your velocity is limited by colleagues treating asynchronous communication as synchronous. You'll either be keeping up with all these Slack channels, or you'll be coding. I personally need about 15 minutes to ramp up when starting to code, and about 15 minutes to bundle unfinished work into a state that's easy to come back to later. Also, don't let teammates underestimate the amount of work it will take to accomplish a task. I feel like there have been a lot of under/unreported hours in previous jobs, so if you're realistic you'll feel less productive than colleagues.