Do any major Canadian cities have safe downtowns?

Define "major", "downtowns" and "safe".

You'll probably find globally the adjusted values for each give a similar response.

Safe for whom?

You gotta recall Canadians have a natural healing factor hence why Keanu Reeves can crank out John Wick films while Daniel Craig is constantly in the hospital doing a fraction of the stunts

I may or may not have been drinking...

Montréal does, safest city I ever been

Toronto is basically Sudan, that’s what NewsCorp told me anyway

Safe compared to what?

Winnipeg has long had a reputation as the "murder capital of Canada", but the annual numbers here are far lower than some weeks in Detroit.

I've worked shiftwork downtown for almost 30 years and never been a victim of (or personally witnessed) any crimes.

The Star just had an article about this Here

But since you didn’t expand on what you mean by safe, I’m not sure what you are looking for

A couple years ago I went on a trip to Calgary. Got wasted and stumbled around downtown with some friends. Came out unscathed, but I can't say for sure how much of that was luck.

(If we can get enough anecdotes, we can call it "data.")

Any major city in the world has crime and "back alley" problems. Canada is no exception. Toronto has plenty of crime. And there are lots of places you should not go.

Toronto PD puts together nice maps: https://data.torontopolice.on.ca/pages/maps

Ontario has one, too: https://www.ontarioca.gov/Police/CrimeMap

You can find this stuff by using your favorite search engine. You can usually find which neighborhoods and streets you would want to avoid.

Pretty much all of them are safe.