I have just enjoyed a holiday to Atlantic Canada and particularly enjoyed Halifax and Cape Breton. You can read my reviews here https://www.silvertraveladvisor.com/blog/destination-features-north-america-canada/maritime-canada-part-1
I loved everywhere we visited and am eager to go back and explore Prince Edward Island and Newfoundland. Halifax waterfront was one of my favourite places.
I’d agree with you that Atlantic Canada is ignored by many UK visitors. We spent a week in Nova Scotia a few years ago and have to admit that we were a bit disappointed – mind you the weather didn’t help as it was cold and wet. The best bit was definitely Louisbourg, which was amazing!
Newfoundland was a different story and we loved that.
We have visited Atlantic Canada a few times now, but it seems to be generally overlooked as a holiday destination. Only six hour flight, and like New England, but even more British.