All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.
It is clear that you do not understand the meaning of the obligatory Tuma’neenah. Tuma’neenah is the tranquility of the body parts, and the limit of Tuma’neenah is that each body part settles in its place for the least time possible (before one moves from one position to another), which is the time required to recite the obligatory Thikr (in that position).
What is meant by the body parts settling in their place is the stability when performing one of the pillars of the prayer. While bowing, it is when one’s hands touch his knees; while prostrating, it is when one’s seven body parts (the face, including the forehead and nose; the two hands; the two knees; and the edges of the two feet [i.e., the toes]) settle on the ground, and so forth. For more benefit, please refer to fatwas 338716 and 200531.
Some slight movements that do not affect the validity of the prayer do not prevent the Tuma’neenah.
All the movements that you mentioned, such as bending slightly forward or backward and swatting the fly away from one’s face and so on, are all slight movements that do not affect the validity of the prayer and do not prevent achieving the Tuma’neenah.
Allah knows best.