Thinking of switching to Fastmail (can you guess why?)
Anyway, I am realizing that Apple mail does not have a widget?
What have you folks found is a mail client with a good widget?…. I was hoping to not get tied into needing a third party all, but it may be necessary.
There a multiple options. Spark (free) has a good one, Airmail (which seems to be slowly, ever so slowly getting its head out the mud) also has one, pretty much all major third party clients do. You have a wide choice and so you will probably decide on what apps has the features you like rather than on the widget availability per se.
I wish Fastmail had one. I like the way Hey’s widgets worked 