I don’t really see how the veto is the problem. The senate already needs a two-thirds majority to override a filibuster, which is assumed for anything remotely contentious that’s not 100% budget-related.
The filibuster does not require a 2/3 majority; it requires only a 3/5 majority. This is still a steep requirement, but it is more doable; we saw that in 2009, where the Democrats (with 2 Democrat-aligned Independents) met that requirement, which is why they were able to pass the Affordable Care Act. Meanwhile, the last time a political party had a 2/3 majority in the Senate was 1966 (a time when, ironically, the requirement to bypass the filibuster was 2/3; it was later lowered to 3/5).
Furthermore, there is no filibuster in the House at all. So essentially, even with the filibuster, you need 3/5 of the Senate and a simple majority of the House to pass something. But the veto changes it to 2/3 in
both houses. The veto has much greater requirements to bypass. In fact, incomprehensibly, it is actually easier to kick a President out of office via impeachment (majority of House, 2/3 of Senate) than it is to override a veto (2/3 of both houses).
The filibuster also is not required by the Constitution at all. While talk of its abolishment seems to have abated for now, I do think it will be removed entirely eventually. But,
even with the filibuster in place, it is easier to get past a filibuster than it is to override a veto, and also the filibuster at least can't be used for budget-related things, whereas the veto can.
The problem is the nationalization of the political parties and political media. When the president is also the leader of the national party, the only time the veto is even a threat anymore is when both chambers of congress are run by the party opposing the president.
No, the veto is a threat even when both are held by the President's party, because the veto power means the President can play a major role in how they craft legislation. He doesn't like something? He can veto it. In practice the veto is rarely used because all the President has to do is say "hey, change this" and they'll dutifully change it because otherwise he can just veto it. This gives the President an absurd amount of power over legislation, something the President isn't even supposed to have much part in.
As for the problem of the nationalization of the political parties, that is something that is essentially unsolvable. They're nationalized, they're strong, and it's what we're stuck with. Basically every country with political parties is like that. Even if we were to adopt some alternate voting patterns like proportional representation, you'd still have national political parties. So if that's unsolvable, it makes more sense to try to fix something in a way that is possibly solvable (even if, admittedly, potentially very difficult).