Mobile data in Canada is notoriously expensive. The official justification is that it's a large, sparsely populated country. The actual explanation is regulatory capture by a cozy/corrupt domestic oligopoly that has successfully lobbied the government to stop foreign competitors.
I remember visiting Canada (this was many years ago) and looking into local prepaid SIM cards. The cost of roaming data was actually cheaper than the data pricing on the local prepaid SIM cards...
When I worked on a project for Rogers I was shocked and surprised to see the prices they charge. Oh and the never ending confusion in those family plans! Hated that work!
Like Canada, Australia is also a very large, sparsely populated country but mobile data is fast and reasonably priced (e.g., https://www.aldimobile.com.au/plans/value-packs/, which I use).