What is the great burden mentioned in Surat Al-Sharh in Allah's saying, "Have We not expanded for you your breast, and removed from you your burden, which had weighed down your back"?

Many exegetes, such as Al-Hasan, Qatadah, Ad-Dahhak, and Muqatil, interpreted Surah Al-Sharh to mean: "We have removed from you your sin that occurred in the pre-Islamic era (Jahiliyyah)," citing the verse: "That Allah may forgive for you what has preceded of your sin and what will follow." Al-Qurtubi clarified that the weight of the sin mentioned for the prophets, despite being forgiven, stems from their intense concern and remorse over it. The forgiveness of sins committed before embracing Islam is a favor from Allah upon His creation and does not contradict the principle that Islam wipes out what came before it.