George Gamow (1904-1968) in “My World Line” p.44
… Thus, Einstein’s original gravity equation was correct, and changing it was a mistake. Much later, when I was discussing cosmological problems with Einstein, he remarked that the introduction of the cosmological term was the biggest blunder he ever made in his life. But this “blunder”, rejected by Einstein, is still sometimes used by cosmologists even today, and the cosmological constant L rears its ugly head again and again and again.
“blunder” - perhaps reflecting more of Gamow’s opinion ...