Thank you for your question. The idea of knowledge which comes from Allah through metaphysical means, rather than through normal means of acquisition has been derived by Muslim thinkers reflecting on verse 18:65 in which Khidr is described as having this trait.
If the definition of ilm al-ladunni is as mentioned above then revelation is the highest form of this type of knowledge, followed by hadith qudsi and then other types of mystical experience. We have plentiful reports about such types of mystical experiences occurring in the life of the Prophet (saw) and the Imams (as). If it seems incoherent that the knowledge of the Imams (as) is only acquired from their study of the Prophetic sunna, then a reasonable explanation would be some level of ilm ladunni. Some commentators have explained ilm al-ladunni as prophethood, and Allah knows best.
May you always be successful
According to Hadeeths narrated from Ahlul Bayt (AS), Kursi of Allah is His Knowledge about Skies and earths and creatures which has got an outer existence, while Arsh is His Full Knowledge about everything, which is more inclusive than Kursi. There are degrees of Knowledge, in which Arsh is deeper, wider and more inclusive than Kursi, that is why we read in the Hadeeth that The Kursi is within The Arsh. In the Hadeeth from Imam Ja'far Al-Sadiq (AS): Everything created by Allah is in the Kursi except His Arsh because it is greater than be included in The Kursi.
Hadeeth of Hanan ibn Sadeer from Imam Al-Sadiq (AS) when he was asked about Arsh and Kursi, he replied: Both of them are great gates of the Unseen. Kursi is the outer gate of the Unseen and Arsh is the inner gate of the Unseen.
Kursi is limited to the skies, earth and what is between them while Arsh is unlimited.
In some narrations we read that The Kursi is the knowledge which Allah granted to His Prophets and messengers, while The Arsh is The Knowledge which no one knows but Allah.
Quran has informed about the future in a miraculous way after the defeat of the Romans. Usually the defeated nations can not stand up strongly in short period to defeat those who defeated them. Allah said in Sura Rum: And after being defeated they (Romans) will defeat (their opponents) within few years Bidh'i بضع سنين which is between three to nine or ten years. The exact number of years was not mentioned because the victory of the Romans on their enemies took few years through many battles and was not in just one year.
'The battles took few years till the Rum defeated their enemies. Quran said: في بضع سنين Within or during few years, which is exactly what happened.
Allah (SWT) created all His creatures for showering on them His countless bounties and unlimited Mercy. We read in Qur'an: (Except those on whom Your Lord Has bestowed His Mercy, and for that He did create them). (Sura 11, verse 119).
Allah never created people to send them to hellfire, except those insist on criminal acts and continue committing injustice and die on such criminal acts.
Allah, The Most Merciful, The Most Compassionate gives every human being thousands and thousands of chances to believe in thr Truth and do good then enter the Paradise.
Allah (SWT) Has promised every one who believes in Him as The One God to go to Paradise as the Prophet Muhammad (SAWA) said: Paradise is the ultimate place for all believers in Allah الجنة للموحدين.
It is not correct the think majority of people since the time of Adam were atheists or non believers. Majority of human beings are believing in The One God which is part of the instinct knowledge even if the cultures and titles are different.
'The Mercy of Allah is much more greater than what we think and He will deal with His creatures with His great Mercy except the enemies of Allah.