Can a believer disobey God in Paradise, as Adam, upon him be peace, did when he ate from the tree?

Paradise is a realm of reward for believers and not a realm of obligation. There are no commands or prohibitions in it; rather, its inhabitants enjoy whatever delights they wish. Allah Almighty has informed us that they are immersed in His remembrance, and their supplication therein is, "Glory be to You, O Allah," and their greeting therein is "Peace," and the last of their supplication is, "Praise be to Allah, Lord of the worlds." They will be inspired to glorify and praise Allah just as they breathe, due to the perfection of their delight in knowing and remembering Allah, and their love for Him. As for Adam, peace be upon him, his entry into Paradise was not as a reward, nor was the obligation lifted from him therein. Rather, Allah tested him there by eating from the tree so that he might depart from it, for a profound wisdom.