… that he’s lying… about any particular issue.

There is a distinction.

Wrong. He is the world's most prolific liar. His lies are almost always laughably inept and transparent.

A great liar would be difficult to disprove.

...is his yearning and exploitation of children and young women

He honestly believes his own lies - a hallmark of magical thinking - a symptom of mental illness.
He has the emotional maturity of a toddler who blames any naughty behavior on his imaginary friends.

Iran is acknowledging the deal, with their own interpretation of the details, but they have confirmed a deal exists.

Period. End of debate.

Until it is validated. It shouldn't even be "Trust but verify" it should just be, verify.

Politifact has trump with 3% mostly true plus 7% true, for 10% true.
18% mostly false, 39% false, 19% pants on fire false. So 76% false.
10 + 76 = 86. 76 / 86 = 88.37 false.

Figures above do not include half truths, which are considered pushes, neither true nor false.
Some false issues may be the result of making an honest mistake, or being misinformed. These do not really constitute lies if they are acknowledged and retracted.
Joe Bidens politifact record was 32% true, 41% false for ~56% false. But Joe had a higher number of incorrect or honest mistakes than trumpass.
To include half truths, trumpass false = 76% of time. Biden false 41%.
Or better said Biden true 59% of time, trumpass 24%, with half truths included.]https://www.politifact.com/personalities/donald-trump/