The greatest blessing of Jannah is not Jannah or the things inside Jannah.
Rather the greatest blessing of Jannah is something even more than Jannah itself. Allah SWT will lift the veil and we will look at His face.
The Quran tells us that when we see the face of Allah, our faces will become bright and shining. (Quran 75:22-23) | (Yasir Qadhi)
Many times when we think of Jannah, we think of the mansions, the rivers, the hoor, the fruits, golden goblets and cups, but we forget that having the opportunity to see Allah azza wa jal is greater than all of these bounties. Allah azza wa jal praises the believers for worshipping Him “bil ghayb”, in the unseen, and in the aakhirah Allah will reward them for this with seeing Him. The believers will enjoy seeing Allah azza wa jal and it will be the most beloved thing they will receive in Jannah. May Allah make you and I among them. | Muslim Matters by Amatullah
Prophet Muhammad ﷺ told us in many narrations that the Believers will see Allah SWT with their own eyes as clearly as they can see the sun and moon (Bukhari and Muslim)