I have successfully reduced my emails substantially by telling students I don't answer email at evenings and weekends, and by simultaneously expanding my office hours and telling them "don't email me - come and see me". That instantaneously gets rid of all the timewasting emails, but still enables serious contact with students who have a good reason to be in touch.
I also as far as possible schedule meetings (e.g. personal tutees, PhD students, research coffees) back to back without any breaks.
Recently I have been saying "no" to absolutely anything that is not getting my own publications out, teaching my modules, my departmental admin job (admissions, currently), or if external involves being paid to do it. That includes travelling, conferences, and important service work like peer reviewing, because I've done a lot in the past, and I'm at in a phase in my life where I have severely reduced time for additional things. I always say "thanks, not now, here's a big list of great/under-utilised alternatives." One day I will have time to do such things again, but not now. And it's the publications and the teaching that really count.
I swear by this article on how to say no
If you don't have one already, and can basically afford one, get a cleaner. And possibly a PA.