That's false. One example:

"According to the Government of Canada Job Bank, the median annual salary for a General Practitioner (GP) in Canada is $233,726 (CAD) as of January 23, 2024."

That's roughly $170,000 in the US. If you adjust for anything reasonable, such as GDP per capita or median income between the US & Canada, that $170k figure matches up very well with the median US general practitioner figure of around $180k-$250k (sources differ, all tend to fall within that range). The GPs in Canada may in fact be slightly better paid than in the US.