The Bible tells us that Solomon did evil in the sight of the Lord. However, this corruption occurred in old age. In his youth he was 'like David his father' and his wisdom was a gift resulting from his humble answer when GOD asked him what he delighted most to have in all the world, & his answer was to have wisdom sufficient to rule the people with justice, since he was a very young and inexperience man. He did not ask for wealth, glory or prestige, but GOD gave him all of these anyway beyond any king before him or since.
The warning about Solomon's later corruption remains:
26"Therefore I run in such a way, as not without aim; I box in such a way, as not beating the air; 27but I discipline my body and make it my slave, so that, after I have preached to others, I myself will not be disqualified." (1 Corinthians 9:26-27).
If you are asking if Solomon was redeemed by GOD despite his 'fall,' New Testament scripture also explains how this is possible, (and likely in Solomon's case):
11"For no man can lay a foundation other than the one which is laid, which is Jesus Christ. 12Now if any man builds on the foundation with gold, silver, precious stones, wood, hay, straw, 13each man’s work will become evident; for the day will show it because it is to be revealed with fire, and the fire itself will test the quality of each man’s work. 14If any man’s work which he has built on it remains, he will receive a reward. 15If any man’s work is burned up, he will suffer loss; but he himself will be saved, yet so as through fire." (1 Corinthians 3:11-15).
Solomon's 'best eternal reward' was likely burned up by his evil choices late in life, but his righteousness will be remembered by GOD and being a doorman in the House of GOD for one day is better than a thousand days anywhere else, (Psalm 84:10).