There was no David and according to the OT, he was a first degree murderer and adulterer, and possibly a homosexual. Their hero was short lived and nothing to be proud of .
On one hand you claim there was no David and on the other you claim there was. David existed, it has been proven.
And David did the same as any other politician except he also publicly admitted his faults (sins). And that is why he was a man after God's own heart.
Only in the Bible. So their make believe man was no one to be proud of.
Is yours after he raped a 9 year old girl, who also happened to be a very close relative. A double whammy incest and child rape frowned upon in the 7C