Very unlikely and speculative that EU should hang Canada out to dry. If aluminum should be a huge problem, it will be regulated to not be too disruptive.
Canada and EU already have a trade agreement, with both Canada and EU facing unstable American policies and market, both have an interest in closer relations.

“Trump’s tariffs on steel and aluminium could see billions of dollars’ worth of Canadian metals being redirected and dumped on Europe. Could this spark a second transatlantic trade war?”