You don’t have to delete them, you need to organize them.
First of all you need a professional and personal account.
Put all linkedin, facebook and any other mail that is personal sent to that file, then you can get to it when you get to it.
On your professional email, make folders and “rules” to send mail automatically to those folders.
I have a NEWSLETTER folder that I send all the reoccurring interesting newsletters that I am interested in. If they are all in the same box, then I can get to them all when I have time.
Religiously unsubscribe from anything you don’t care about. Also mark SPAM. It saves so much time in the long run.
I try to handle filing email as I go, but if I can’t, I always take care of everything before the end of the day or at worst, first thing in the morning.
Hope that helps!