Far from an expert, but I think it depends on the horse.
About a million years ago when I used to work at summer camps, we’d get a lot of Standardbreds off the track. Some pacers wouldn’t trot or canter ever, some pacers had wonderful trots and canters. Some trotters are fast/strong at the trot, some settle in fine.
My pacer mare, who never paces these days, is very quick to offer the canter.
If you pick up one through an aftercare organization that starts them under saddle, many have already had experience at the canter under saddle. I know that was a big selling point for me with my mare.