What is the reason for the delay in provision – such as marriage – despite daily recitation of Surat Al-Baqarah and abundant seeking of forgiveness? And do weakness of faith or lack of contemplation play a role in this? And is it a condition to continue reciting Surat Al-Baqarah for 40 days for the provision to come?

There is no evidence that reciting Surat Al-Baqarah or any other surah (definition) directly leads to marriage or sustenance. Whoever seeks these should fear Allah and be persistent in supplication during times when prayers are answered. Seeking forgiveness is a cause for sustenance, children, and relief from distress, but the acquisition of sustenance is not always immediate, and sins may prevent it. Supplication is a cause for a response, and whoever's sustenance is delayed should be patient and repent from sins.