Is committing to reciting Surat Yusuf after the 'Asr prayer every Monday and Thursday, based on a vision in a dream, considered an innovation (bid'ah) or is it permissible?

There is no evidence for a time of answered supplication on Mondays and Thursdays after Asr prayer. The hour of answered supplication clarified by the Prophet, peace and blessings be upon him, is the last hour of Friday. Specifying the recitation of a particular Surah at a particular time has not been established by the Sunnah, and it is feared that it may be an innovation.

To achieve what a Muslim desires, he must adhere to Allah's law and repent to Him, observe the obligatory duties and abandon prohibitions, associate with righteous people, and strive in drawing closer to Allah.