Is setting a specific number for seeking forgiveness (Istighfar) or glorifying God (Tasbih) before sleep or after prayer considered an innovation (bid'ah), knowing that innovation is the creation of something not found in the religion?

Absolute remembrance (dhikr), which has not been restricted by a specific number in the Sunnah, is desirable to perform in abundance. However, it should not be limited to a specific number that one adheres to regularly, like the restricted, sunnah-prescribed remembrances. What is forbidden is the belief in a virtue that has not been established by Islamic law, or the regular adherence to a specific number not mentioned in Islamic law, making it like a prescribed sunnah form. It is not permissible for anyone to legislate for people a type of remembrance that is not sunnah-prescribed and make it a regular act of worship that people adhere to.