How was Trudeau held accountable besides a small slap on the wrist? And regardless the Notwithstanding clause is more than enough to extinguish anything in the CoR.
Trudeau became so desperately unpopular that he was compelled to step down.
As for legal responsibility and repercussions, that's a process that is still in motion. The law moves slowly in Canada.
This gets at the concept of accountability for those at the top of government. This is an issue in all governments, not just in Canada. A good parallel would be the United States. The list of actions the current administration has taken which have been determined illegal is astounding, yet no one is held accountable in a way that would deter future breaches of the law.