Canadian here, Swiss Chalet 1/4 rotisserie chicken is my go to if it is available and will actually get this a couple times a year while in my own city.
If I only have the big US chain options on a road trip, I will usually go for BK whopper followed by maybe at A&W (not super familiar with the menu, so would just go with whatever sounds good at the time). I would have to be really desperate to consider McD’s and can’t remember the last time I ate there, but thankfully where there is a McDs there is usually a BK nearby.
I agree with whoever said Canadian fast food has gotten sweeter, I noticed that as well, especially the bread.
ETA, currently my favourite convenience food to have when I am in my own home is frozen meals I purchased from the local market/food truck/restaurant collective (a great thing that came out of the pandemic). Currently I have a stash of New Zealand meat pies, vegan Indonesian “chicken” curry and kung pao, and gourmet dumplings in my freezer. I rarely eat out now, this is just too convenient to have some of my favourites on hand to reheat when I don’t want to cook.