Shakuni's advice to Duryodhana right after Rajasuya?
Yudishtira’s Rajasuya was conducted grandly. Unimaginable riches came into Indraprastha. Powerful kings had to go back without entering the city because there were so many guests already. The Pandavas had invited the Hastinapur royals too. Duryodhana and Shakuni stayed back after the Rajasuya. One day when he was wandering in the Maya sabha, he fell into water and then bumped into a wall. Bhima, the twins and Arjuna laughed.
Duryodhana was already furious about how rich Indraprastha was and how the Pandavas were being respected by everyone, even the most powerful kings in Bharatvarsha. After the Mayasabha incident, he was even more angry because he felt he was been terribly insulted.
He left soon after and on the way back, he told his uncle Shakuni that he was very upset at the Pandavas’ prosperity. So upset that he wished to kill himself. At this time, it was surprisingly Shakuni who told him he was wrong. He said that the Pandavas made Indraprastha prosper with their own strength and ability and so Duryodhana should not jealous.
Duryodhana wished to go attacks them but Shakuni told him that he would never be able to win against the Pandavas.
Although it is Shakuni who later offers to steal Indraprastha in the dyuta game, he does give good advice to Duryodhana first- to stop being jealous and to focus on getting wealth by his own efforts.