You have to be online on messaging services/contactable by email with quick response during normal hours, making it very hard to do much else in this time.
Covid has meant more people working remotely, but hasn't changed working schedules that much from what i have seen here at least.
What's "online" with a "quick response" - suppose you step away for 45 mins to work out? Is someone giving you a hard time because your response time to an email or a Slack message is not immediate? Does that question or inquiry need to be handled that quickly?
Lots of things like this seem like a failure to set expectations. We're allowed to deliberately block our calendars, right? That might mean you close your email and do an hour of work solid, or work out, or run an errand. But it's possible, with some deliberate calendar planning, and frankly transparency with those expecting something from you.
"I won't be available for the next 45 mins because [X]" is a pretty easy statement to deliver
We still live in a world full of companies that don’t allow software engineers to work in their best environment.