You say you respectfully disagree, but the points you make about LBJ and Nixon being bad in a variety of ways have little to do with what I wrote, except maybe the 'worse and worse politics' bit.
It's not that I'm claiming politicians weren't corrupt or bad in various ways in the past, what I object to is the lazy 'they're all the same' rhetoric that lets politicians off the hook and pushes people to resign themselves to corruption because they can't help it, it's part of what makes a politician.
The difference however is that Nixon was a smart politician who had policy ideas that he tried to implement on a wide range of topics, and during whose presidency lots of important steps were taken on foreign policy, health care and social security, environmental policy, welfare reform, etc. - obviously not all of them his own personal achievements and most involving Congress, but still.
The difference between Trump and previous presidents isn't necessarily that he's more corrupt or morally more reprehensible. It's that he doesn't give a fuck and can't be bothered to actually put in any work and develop actual policies. Even when the Republican-led Congress during his presidency was trying to pass tax cuts or other priorities that he supposedly wanted, his rhetoric was changing from day to day and he was often hurting passage as much as helping it, because he had no real idea of what the end result should be, caring only that whatever it was would make him popular.
Also on the topic of lying - yes, essentially all politicians lie sometimes. They know the actual facts but still say the opposite because it makes them look better, or they lie by omission. And sometimes they flip-flop on an issue, knowing that it looks bad but having reasons to make it worth it. But with Trump it's not so much lying or flipflopping as bullshitting: he doesn't know / can't be bothered to have to remember any actual facts, so instead he just makes random stuff up without caring in the least what resemblance his statements bear to the actual facts, or to what he said on previous occasions. Probably everybody knows some people who often do that in their lives, it's not necessarily that harmful, but when Trump does it, somehow a lot of people filter out only those parts that sound good to them and then delude themselves into thinking that Trump is actually going to help them and never mind all those other things he said to the contrary.
Though it must be said, this complete lack of consistency and vision is in some ways also a good thing - when liberals are going on about the scary Project 2025 plans or even Trump's 'fascism', they aren't taking into account Trump's track record and the likelihood that, just like the tax cuts, he will be hindering such plans as often as he'll boost them.
A hell of a lot better than if we had all collectively accepted for those thousands of years that politicians are all inevitably going to be corrupt and there's no point doing anything about it.