Email is a productivity killer. At a minimum, I would suggest only checking email once every couple of hours, nothing that's truly urgent should be sent by email anyway. Have a look at this video from the excellent Leila Gharani - the simplest version would be to have Outlook closed except for certain times of the day, e.g. 8am, 11am, 2pm, 4pm. Block half an hour at each of those times in your diary to go through email but don't look at it otherwise.
I haven't worked in an actual office for years (I WFH long before the pandemic) but the noise and chatter can be v unhelpful when you're trying to focus. Do you have headphones? (I assume people still do this in the office, put noise cancelling headphones on when they need to focus). If you've got something you really need to concentrate on, can you do that away from your desk, i.e. in a meeting room or quiet space somewhere?
I would maybe limit yourself to no more than 1 hour on a Sunday afternoon, so you can clear off the most urgent stuff ahead of Monday. And consider this a short term measure whilst you're finding your feet, not something you should keep permanently.
Have a look at what you're spending time on. These chasing emails, is it just progress updates on ongoing projects? Can these senior managers have access to this information in a way that doesn't involve hassling you all the time, e.g. shared tools like Microsoft Planner? Project update reports at set times in the week, like maybe a Wednesday check-in or similar?