Canada

Um, yeah, Canada has a Constitution and the Charter is a part of it:

The Constitution Act, 1982 gave Canada complete independence from Britain. Months of negotiations between the federal and provincial governments were held to determine how to “patriate” the country’s last British-held powers from Britain. The resulting Constitution Act, 1982 made several changes to Canada’s constitutional structure. The most important were the creation of an amending formula (the criteria that would have to be met to make future changes) and the addition of the Canadian Charter of Rights and Freedoms.

https://www.thecanadianencyclopedia.ca/en/article/constitution

So, yeah, I am Canadian and laws in Canada can be unconstitutional. If you are curious about it our constitution, try finding basic information about it before condescending to teach someone else about it.

Canada has unreasonable search and seizure protections

It’s section 8 of the Charter

However our next PM (polling wise) said this when speaking to police in regards to the constitution limiting their powers

“We will make them constitutional, using whatever tools the Constitution allows me to use to make them constitutional. I think you know exactly what I mean,” Poilievre told the crowd.

Yeah, I do understand that we, like the US, also have a Constitution. Do you? Our Constitution includes a Charter of Rights and Freedoms which protects against unreasonable search and seizure. You should look it up sometime. Here's a starting point from the Canadian Encyclopedia:

https://www.thecanadianencyclopedia.ca/en/article/constitution

Edit: I should also say that protections against unreasonable search and seizure long predate the Canadian and US Constitutions and are derived from our countries' common lineage back to England. If you are ever confused about why Canada and US have many similar rights and freedoms, it is because both Canada and the US were British colonies before achieving independence.

The breathalyzer isn't the problem. It's a free pretextual stop where they can look inside your car and decide if they want to hassle you over something else

But it doesn't read BAC. It just detects organic compounds with methyl groups and the courts assume it is alcohol. That's usually a pretty safe bet if the person is also clearly inebriated. But now people who work with organic chemicals either at home or at work could get charged even with 0 actual BAC. Paint your bathroom with oil paint and have toluene in your system? Believe it or not, straight to jail.