I respect facts more than opinions so that's commendable. However, it's not quite as clean cut as you like.
It's a fact that Trump actually did take the salary. Though, exactly how much is unknown.
While he did donate most of his salary to charities and government organizations each quarter, his final two quarterlies are unaccounted for. But, he did put in some money to round out the donations to $100,000. How much he made up for or if he actually paid them from his own pocket can only be speculated.
In total, he donated at least $1,096,662 as well as 303,338, again to round out the donations. His final two quarterly checks in 2020, would've amounted to $156,666. Assuming he did pay the difference from his own pocket to round up the quarterly donations, he ended up actually paying more than he took out of the office with something like $146,672.
But as he did apparently accept the final two checks; not to mention every donation could be written off in taxes, to say he didn't benefit financially is not entirely accurate.
To be fair, even if he did pocket the final two checks and someone else was rounding out the donations, the lowest pay that I could find for a federal representative is something like $174,000 a year. Compared to Trump's two unaccounted for quarterlies, that would mean might have earned at minimum $156,666. So, if you wanted to at least claim that he was the lowest paid elected official in the federal government while in office, you'd be right.