Is it permissible to increase the number of Rak'ahs in the Tahajjud prayer in the Grand Mosque beyond eight Rak'ahs, following the Sunnah of the Prophet (peace be upon him)?

Al-Bukhari narrated that Umar ibn al-Khattab gathered the people for Tarawih prayers behind one reciter, and he said, "What an excellent innovation this is." And the people in Umar's time used to pray twenty-three rak'ahs. The hadith of Aisha, which states that the Prophet did not exceed eleven rak'ahs in Ramadan, does not indicate a prohibition of increasing the number, and no specific number of rak'ahs for Tarawih prayers has been authentically reported from the Prophet, peace and blessings be upon him.