This problem is nothing new, though it sounds worse than ever.
Pre covid I was flying thru Pearson at least once a month. It was almost always a shit show. From the baggage check, to security (especially) to baggage claim, everything took way too long.
Simply put, there were never enough people working there. Ever.
Security was the worst. You'd be in the rat maze and it would be massive and you'd get up to the front of the line and they'd have only 2 or 3 (max) doors open. (If I recall, they have 10 doors.). I would always get angry. And it never helped how slow the lines were due to the passengers being so unorganized.
Baggage check was the same. Air Canada has these huge long counters with 16 check-ins and 2 of them would be staffed.
Here's a dumb idea......
Hire more staff. Pay more to attract people.
But they don't want to. They just want to work the shit out of people. Unless the gov't comes down on them, nothing is going to change.