Are bothersome thoughts related to intentions behind deeds, the fear of showing off, envy, and arrogance, repeating prayers due to extreme forgetfulness, and the emergence of thoughts that contradict religious convictions considered to be whisperings (waswas) or weakness of faith?

The enquirer is afflicted with waswasah (whispers/obsessive thoughts). Its cure lies in ignoring and distracting oneself from it, seeking refuge in Allah, and frequently remembering Him. There is no objection to consulting mental health specialists. You have mentioned the reality of showing off (riya’), and you have reviewed fatwas regarding envy (hasad) and arrogance (kibr). The prayer in which you did not experience khushu’ (humble submissiveness) is nevertheless valid, and you are not required to repeat it. It is recommended to maintain the performance of sunan (prophetic traditions) and nawafil (supererogatory prayers) to compensate for any deficiency in the obligatory prayers.