i don't think email is the crux of the problem, tbh.
In fact this is already automated to the extreme, with stock replies for applicant emails, OOO with rerouting whenever i m not in, etc.
I hesitate to say this, to not sound ungrateful for the advice but: i am very effective at managing emails, diary, booking system, etc
Sadly, time is a finite quantity. As I got more and more senior, i (like most people here) did not get the secretary that the previous generation of profs had, and i still find myself doing all sort of super basic admin tasks (e.g. today, chasing HR to find out who is not pressing the correct button holding back job applications) whilst accumulating more and more internal and external responsibilities.
REF got thankfully pushed back, because, lucky me, I am the REF person for my unit. I tried to say no, but apparently, this is the price you pay for promotion. There is no amount of email management which will take the sting out of that one.
i don t want to be spikey, i really don't. But the job feels, often, like eating soup with the hands tied behind my back. I just really really would like my day to be filled by interesting creative pursuits, rather than dreary tasks.