Is a prayer invalidated if it contains many errors, additions, and omissions, and the worshipper does not perform the prostration of forgetfulness (sujood al-sahw), or is it acceptable because the prostration of forgetfulness is a Sunnah and not obligatory?

If errors in prayer are due to waswas (obsessive whispering), the worshiper should continue their prayer and not pay attention to those errors, as mentioned by Ibn Uthaymeen.

Ibn Uthaymeen said: 1. Doubt resulting from mere illusion does not affect the prayer. 2. The abundant doubt of one afflicted by waswas should not be given attention; they should continue their prayer. 3. Doubt after completing the prayer should not be given attention, unless the worshiper is certain they omitted a pillar.

It is prescribed for one afflicted by waswas to perform two prostrations after the tasleem to spite Satan, and their prayer is not invalidated by omitting them. Al-Akhdari mentioned that one afflicted by waswas should not perform what they doubted, and should prostrate after the tasleem, whether they doubted an increase or a decrease.