The US federal government is very strong compared to many countries, just limited in where that power can be applied... in theory. In practice, the insanity that is a precedent-based judicial system over time means that it's all just a disorganized mess where on one hand the Feds can straight up prevent you from boarding a plane, ever, without any semblance of due process (this is not normally a power you'll find in other countries), and yet can't regulate many mundane things like firearms.

However, there is a very solid case for a weak federal government, and it is simply that US is a country that's way too big for any coherent national policy on most matters that we've currently pushed there. It's such a vicious fight because it's half the country trying to bludgeon the other half into submission, motivated by the knowledge that, if you yield, the other guy will pick up this huge club and do the same to you. This will continue until the country breaks down unless we dial it down to state level and accept the fact that other states may have laws and lifestyle that is despicable or horrifying to us in some ways. Either that, or we might as well just break the whole thing apart now and not wait for it to happen in a more violent manner.

Compared to wich countries,

The US is a massive country, with the populace far removed from the decision making. I believe this is the core problem.

States are not printing billions of dollars and shipping it overseas or wholesale spying on their populace for the purpose of political manipulation.

The two-party system isn't so heavily institutionalized "by law". The law generally gives advantages to parties that pull in more than x% of the vote, and it so happens that the first-past-the-post system of electing representatives makes it very difficult for a third party to take root.