The Minister of Transport has recently announced a one-year extension of the current prohibition of yachting in Canadian Arctic waters: Government of Canada announces one-year ban for pleasure craft and cruise vessels.

The text of the new Interim Order has not yet been published, but will presumably track the wording of the existing Order that expires February 28th.
 
Related news item about Kiwi Roa's successful West-East transit last year: Nunatsiaq News: "No 'right to innocent passage' through NW Passage for NZ sailor". To the best of my knowledge, no fine has been issued regarding that voyage.

Yes, the Atlantic provinces have enacted de facto border controls / quarantine requirements. Last summer that was sufficient to stop me from travelling to Nova Scotia, where I was scheduled to teach two RYA courses.

The good news is that the 'Atlantic Bubble' has a low incidence of COVID-19, and people inside it are able to lead relatively normal lives. It is probably the nearest thing to New Zealand as one can find in the Americas. Friends who base their yacht down East (usually in Newfoundland, more recently in Cape Breton Island) did the quarantine, enjoyed two months of cruising, and did not return to Ontario until November.