The competitive, efficient, and circular transition of the current supply chain due to successful interaction between I4.0 and circularity is depicted by the current state of theory and practices. In spite of several proposed theoretical frameworks by academicians and available literature for this complex shift of linear supply chain to CSC, there is still a deficiency of organised, company-oriented, and practical approaches which is capable of transitioning linear supply chains towards circularity. In addition, operational challenges, urges, and constraints hindering CSCs emergence are still overpassed and, therefore, present a vast area of research in this domain. The theoretical gaps or voids in the literature pertaining to CSC-I4.0 are uncovered through a systematic gap analysis, and the potential barriers are investigated through a comprehensive literature review in this paper, with a major focus on SMEs. This two-fold field research area of Circular Economy and Industry 4.0 technologies is more comprehensively studied by extensively identifying the related scholarly articles using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) method. This investigation rigorously reviews existing literature, encompassing 45 articles thoroughly analyzed, consolidated, and categorized across various dimensions. The hindrances in the metamorphosis of linear SC to CSC are then grounded into five categories and exhaustively studied, identifying the 7 most emphasized, critical, and recurrent realistic barriers. The study highlights the need for a strategic blueprint to act against CSC intransigent voids and realistic hindrances as in this research and act as cues for the stakeholders like policymakers, researchers, and managers.