The questioner asks about placing a Mushaf as a Sutrah to pray towards?
Answer: This is Makrooh, this is not necessary. This is prohibited. The Salaf prohibited that as is in the book Kitab ul-Masaahif of Abu Bakr Ibn Abi Dawood rahimahullah.
Ibrahim an-Nakhi rahimahullah said: “I met our scholars and they prohibited that”* ie. placing the Mushaf as a sutrah. Ibrahim met a group of Companions or a number of Companions.
* The narration the Shaikh is referencing is the following:
عَنْ إِبْرَاهِيمَ قَالَ: كَانُوا يَكْرَهُونَ أَنْ يَجْعَلُوا فِي قِبْلَةِ الْمَسْجِدِ شَيْئًا حَتَّى الْمُصْحَفُ يَكْرَهُونَهُ
Ibraahim an-Nakhi rahimahullah said: They (the Companions) used to dislike that they put something towards the Qiblah of the Masjid , even the Mushaf. They disliked it.
[Kitab ul-Masaahif no. 683 and the chain is Saheeh]
[Taken from: https://aloloom.net/upload/h/fatawa/226.mp3 ]
Translated
Faisal ibn Abdul Qaadir ibn Hassan
Abu Sulaymaan