https://www.pbs.org/newshour/nation/robert-e-lee-opposed-confederate-monuments

"As regards the erection of such a monument as is contemplated," Lee wrote of an 1866 proposal, "my conviction is, that however grateful it would be to the feelings of the South, the attempt in the present condition of the Country, would have the effect of retarding, instead of accelerating its accomplishment; [and] of continuing, if not adding to, the difficulties under which the Southern people labour."

...

"He said he was not interested in any monuments to him or – as I recollect – to the Confederacy," explained James Cobb, history professor emeritus at the University of Georgia, who has written about Lee's rise as an icon.

"I don't think that means he would have felt good about the people who fought for the Confederacy being completely forgotten," Cobb added. "But he didn't want a cult of personality for the South."