Will the two rak'ahs of supererogatory prayer in the Sacred Mosque compensate for the deficiency of prayers on the Day of Resurrection, knowing that they do not suffice for 200,000 rak'ahs in other prayers?

What has been mentioned about making up for obligatory prayers with supererogatory ones is correct. Prayer in al-Masjid al-Haram is multiplied a hundred thousand times, but this multiplication is in reward and does not substitute for missed prayers; rather, they must be made up. As for the multiplication encompassing supererogatory prayers, there is a detailed explanation for that. It is hoped that for one who performs many supererogatory prayers in the Haram, this will be more effective in compensating for deficiencies in their obligatory prayers.