The real weakness of P.R. is that there is no accountability for individual MPs, they become slaves to the party.
Given that we are already suffering from that in our current FPTP system, then I would argue we should either fix it by making MPs relevant again (which we seem incapable of), or we have to acknowledge that MPs don't represent people in their riding, they represent the party, and so we might as well adopt P.R. and get the benefits (proper representation for voters) since we're already accepting the drawbacks.
I'm okay with hamstringing the government. As COVID has shown, when it matters, they can make things work as they do fear the wrath of the ballot, but when they try to take advantage (like the Liberals did at the outset of COVID by trying to pass legislation that would essentially make them our new overlords), the ability to hamstring them is pretty important.
FPTP only works when individual legislators are empowered, it relies on that. We don't have that right now.