Which is better and carries a greater reward for the Eid prayers before the Imam enters: Tasbih and remembering Allah with the congregation, or performing supererogatory prayers?

If you enter the Eid prayer area to perform the prayer, pray two rak'ahs as tahiyyat al-masjid (greeting to the mosque), then sit and remember Allah, especially by reciting takbir. Do not perform any other voluntary (nafilah) prayers at this time, as they are considered makruh (definition) (disliked) by scholars. The Eid prayer area has the ruling of a mosque, so tahiyyat al-masjid is prayed in it, but no other voluntary prayers should be performed before or after the Eid prayer.