Is there another acceptable opening other than "Dear" - that always makes me feel a bit squeamish
It gets to me, too. But knowing that the following is true:
"Dear" is, historically, just a rote, meaningless salutation.
I have forced myself to use it for job-related emails. It freaks me out a little less now having "dear"-ed a wide variety of strangers this year. Knowing that is absolutely required makes it easier to use, too. I will not "hi" anyone professionally again.