I don't see it as being hard to pronounce if you take the time to think about it. The majority (if not all) QA words start with a hard K sound. And "drea" rhymes with
Andrea. Simple. And it's got no more spelling issues than
Catherine,
Katherine,
Cathryn,
Kathryn, Catheryn,
Katheryn, and so on.
It's not my style, but it's a nice name as is - no need to anglicise it at all.