European parliamentary democracies seem a bit harder to run off the rails into totalitarianism. There's been some recoveries (for now at least) among EU countries from the same kind of nationalistic/fascistic trends happening here in the USA.

But a parliamentary democracy can't be implemented in the USA, for the same reason that none of these thought experiments could be implemented.

It's not about party identities and names and platforms, or shuffling some bodies or roles around in the existing context. It's about actual power and control. The USA is an oligarchy, always has been. The actual power over 'civil liberties' and what gets funded or not and increasing or decreasing 'social justice' or 'environmental responsibility' is not held by the "United States Government" as a political entity. The government has always served first and foremost the oligarchs, and actual democracy is counter to their interests. A thin veneer will suffice; if that starts to wear through, as it is rapidly doing, it's back to good old outright dictatorship.

To make any true change in the de facto oligarchy would require a degree of mass collaborative action by citizens that is functionally impossible in the USA.

As Ben Franklin may or may not have actually said, "if we do not hang together, we shall surely hang separately." The USA is the most hyper-individualistic society of humans on the planet, and getting more so every day. We are doing the opposite of hanging together, and we'll get the consequences of that.