In retrospect, while deactivating / deleting my accounts seems like a big deal, the real battle was fought some time before.
I've never been much of a Facebook user but took the decision a number of years ago to unfollow a whole bunch of people and restrict it to just family and a few select "real world" friends.
For Twitter it was the decision to stop tweeting in 2016 which, by extension, meant that I also stopped checking.
Killing my accounts is definitely more final and removed the last vestiges of temptation but I honestly don't think I could be tempted anyway.
It just feels good to have free myself from a false need to keep those aspects of a fractured online identity.