What is the guideline for movement that does not invalidate prayer, and does taking many steps within the prayer invalidate it?

Scholars differ regarding the movement that invalidates prayer. Some say it is what is deemed excessive by custom, while others say it is what makes an observer think that the performer is not in prayer.

Sheikh Ibn Uthaymeen holds that an action invalidates prayer if it is: long according to custom, not out of necessity, and continuous.

Regarding a worshiper walking five or six steps to close a gap, the Shafi'is consider this a frequent action that invalidates prayer if the steps are continuous.

Some Hanafis, on the other hand, believe that prayer is not invalidated by a worshiper walking to close a gap in the very front row, but it is invalidated if they walk to another row.

As for the Malikis, they hold that prayer is not invalidated by walking the distance of three rows to close a gap.

Therefore, walking five or six steps is considered a frequent action that invalidates prayer according to many scholars.