The US system is far more dysfunctional — we have the Senate, which ensures that there isn’t an opportunity to conduct a vote along any line!

The real lever of power in congress is the parliamentary process in the Senate.

I’m not so sure. A system in which a party that wins only 34% of the vote is given a near supermajority in the legislature and control of the executive seems pretty dysfunctional to me.

In the US Senate, 80% of the votes represent 46% of the population.

Wyoming has more sheep than people, but they are represented on the same basis as California, Florida, etc.

I think right now that's not as much of an issue as the 80/46 numbers suggest. If, say, the Democrats had 80/100 votes just from representing that 46% of the population, that would be bad. But that's not how the two parties distribute right now. Big states can be Democrat (California, New York) or Republican (Texas, Florida). Small states can be Democrat (Vermont, Delaware) or Republican (the Dakotas).

The Republicans do end up with a small (up to 5%) advantage in the Senate but that's it. Nothing remotely close to the Labour party getting a near supermajority in the Commons from 34% of the vote. It's simply much much worse in practice than the situation in the United States.

Yeah, the real difference is that in the US, there is a separate election for president. In the UK, as in many other countries, the party that wins parliament gets to form the government (and determine the prime minister or whatever the title of the de facto head of the executive is). In some countries this is complicated by multiparty systems where coalitions are required, but the general idea of aligning the legislative and executive branches in this way is fairly common.