Did any of the scholars say it is permissible to completely conflate between the madhahib (schools of thought) so that one's soul may be reassured about past acts of worship?

Some scholars have opted for the permissibility of taqlīd (following a qualified scholar) in talfīq (combining different juristic opinions), among them the eminent Hanbalī scholar Marʿī al-Karmī. Dr. Wahbah al-Zuhaylī mentioned that the claim of a consensus (ijmāʿ) on the impermissibility of talfīq requires evidence, and he pointed to a clear difference of opinion among scholars on this issue.