Well the structural issues have been present for some time but the influx of newcomers during COVID did not help the situation. Not saying it is right, but these newcomers have become a scapegoat and it's stoked the flames of xenophobia which was previously never an issue in this country.
Also QC for all it's local issues has largely been insulated from "over-immigration" due to the language requirements. If your only experience is there you may not be aware of the scale of the problem.
It has not been insulated at all, there are tons of federal immigration pathways made easier for french speaking immigrants. According to this https://www.statista.com/statistics/444906/number-of-immigra..., Ontario does seem over-represented.
I'm not saying over-immigration has no downsides, clearly it did not help our overstrained system, but to say it caused it is to willfully blind ourselves to the structural issues that lead to these issues in the first place. i.e. they will never be fixed