What is the ruling on reciting Ayatul-Kursi before saying Astaghfirullah three times immediately after the Taslim in the post-prayer remembrances, in order to avoid being preoccupied with returning the greeting and speaking?

The dhikr (remembrance of Allah) after prayer is recommended, not obligatory, and does not require a specific order. However, it is better to perform it in the order reported from the Prophet, peace and blessings be upon him. He used to begin with istighfar (seeking forgiveness) three times, then say: "O Allah, You are As-Salam (the Source of Peace), and from You comes all peace. Blessed are You, O Possessor of Majesty and Honor." Then, "There is no god but Allah alone, He has no partner. To Him belongs all sovereignty and all praise, and He is over all things competent," and other well-known adhkar. After Fajr and Maghrib prayers, he would add ten times: "There is no god but Allah alone, He has no partner. To Him belongs all sovereignty and all praise. He gives life and causes death, and He is over all things competent." Then he would say Subhan Allah (Glory be to Allah), Alhamdulillah (Praise be to Allah), and Allahu Akbar (Allah is the Greatest) thirty-three times each, concluding with: "There is no god but Allah alone, He has no partner. To Him belongs all sovereignty and all praise, and He is over all things competent." Then he would recite Ayatul Kursi, and Surahs Al-Ikhlas (definition), Al-Falaq, and An-Nas once after Dhuhr, Asr, and Isha prayers, and three times after Fajr and Maghrib prayers. Therefore, there is no harm in reciting Ayatul Kursi after saying istighfar three times, even though this is not the preferred order.