What is the ruling on seeking forgiveness ten times, then glorifying, exalting, and magnifying God (saying Subhanallah, Alhamdulillah, La Ilaha Illallah, Allahu Akbar), and repeating that several times during one's free time; and is this action considered an innovation (bid'ah)?

Performing a dhikr (remembrance of Allah) with a specific, non-prescribed number is considered an additive innovation (bid‘ah idafiyah) if one adheres to it and considers it a sunnah. However, if there is no adherence or belief that it is a sunnah, then there is no harm in it, especially if it is done during leisure time and without believing it to be a sunnah; rather, it is a virtuous act. The remembrance of Allah is divided into two categories: that which has been restricted with a specific number for its virtue, and that which has been left unrestricted and not limited by a specific number. In the latter case, it is not legislated to adhere to a specific number. Specifying a particular dhikr to a specific time and number requires evidence; otherwise, it is considered an additive innovation.