Is it forbidden to feel that Allah is greater than everything when saying "Allahu Akbar," and is it obligatory to feel the عظَمة (greatness/magnificence) of the Kursi, and is it obligatory to imagine the 'Arsh (Throne)?

One must believe that Allah is greater than everything. This is supported by what Ibn Abbas narrated: "Allah is the Greatest, Allah is greater than all His creation. Allah is mightier than what I fear and dread. I seek refuge in Allah, besides whom there is no god, the Sustainer of the seven heavens from falling upon the earth except by His permission, from the evil of your servant so-and-so." As stated in the commentary on Al-Aqidah Al-Wasitiyyah, magnifying Allah is done with both the tongue and the heart. A person says "Allah Akbar" (Allah is the Greatest) when ascending and rising, and "Subhan Allah" (Glory be to Allah) when descending. The Kursi (Footstool) is immense and established by textual evidence, and the seven heavens compared to the Kursi are like a ring cast in a desert. There is no harm in imagining the Kursi and the 'Arsh (Throne), for they are among Allah's creations concerning which reflection is permissible.