“they should rejoice...better than what they accumulate”
In this reading, the third person plurals refer to the Believers.
فَلْيَفْرَحُوْا...تَجْمَعُونَ
fa-l-yafraḥū...tajmaʿūna
“they should rejoice...better than what you (pl.) accumulate”
In this reading, the point is addressed to the unbelievers, so the latter verb is in the second person plural. The first verb still refers to the Believers.
فَلْتَفْرَحُوْا...تَجْمَعُونَ
fa-l-tafraḥū...tajmaʿūna
“you (pl.) should rejoice...better than what you accumulate”
In this reading, both second person verbs are addressed to the Believers.
Explanation
These readings provide complementary meanings, i.e. the Believers should rejoice in the guidance of the Quran, which is superior to any of their worldly possessions and raises them above those who possess the world's riches [al-Alusi].
He has revealed to you ˹O Prophet˺ the Book in truth, confirming what came before it, as He revealed the Torah and the Gospel
Explanation
These readings provide complementary meanings, i.e. the Believers should rejoice in the guidance of the Quran, which is superior to any of their worldly possessions and raises them above those who possess the world's riches [al-Alusi].