Isn't Trudeau term limited at this point?
Canada does not have term limits. Trudeau is free to be PM as many terms as he can either win elections or scrounge up coalitions in parliament.
Speaking of which, would there be a chance for the Canadian Constitution to be re-written, to allow for infinite terms, like how Xi and Chavez did?
One of the few somewhat nice things about the Canadian constitution is that it is nigh impossible to amend anything, so it is nigh impossible for the fuckers in charge to force their agenda into the constitution. I think the same general sorts of roadblocks could be said to be present in the US (?), but in order to make most changes to the Canadian constitution, they need to meet the parameters of something called the "7+50 formula," wherein for a constitutional amendment to pass, it must have the support of 7/10 provincial legislatures ( 2/3rds majority of provinces), or a collection of provinces representing at least 50% of the population. In practice, there is so much discord between the provinces that it is practically impossible for these parameters to ever be met.
One of the only times it was actually accomplished was through deception, in a Canadian event termed the "Night of the Long Knives" as an homage to the German event; considered a stab in the back to Quebec by the Feds and every other province. Essentially they sent everyone home for the night, and then called everyone other than the Quebec delegates back, to negotiate a new constitutional deal overnight behind Quebec's back. Partly as a result of this, Quebec has ever since refused to participate in basically anything constitution-related, which means Canadians get to hear politicians repeatedly saying "Now is not the time to re-open the constitution!" even though Canada effectively does not have a functional one.
That's also speaking generally, and there are specific cases where full unanimity is required like in the EU, which in Canada is just never, ever going to happen. Between Quebec and Ontario despising each other, and Alberta hating the both of them, unanimous agreement about anything is extremely rare in Canadian politics. Even if it seems like something that ought to be unanimous, someone's obstructing for ulterior reasons.