Introduction

The relentless evolution of wireless communication networks continues to reshape the technological landscape, propelling towards an era of ubiquitous connectivity, unprecedented data rates, and innovative applications. With wireless technologies entering the Sixth Generation (6G) around 2030, the demand for efficient spectrum utilization, energy efficiency, and seamless integration of communications, sensing, and computation has never been greater. To realize these diverse requirements, Reconfigurable Intelligent Surfacesris (RISs) have emerged as a revolutionary paradigm, capable of fundamentally redefining the design and operation of wireless networks, bringing forth the prospect of smart programmable wireless environments (Di Renzo et al. in EURASIP J Wireless Commun Netw 2019(1):1–20, 2019; Calvanese Strinati et al. in IEEE Commun Mag 59(10):99–105, 2021; Alexandropoulos et al. in EURASIP J Wireless Commun Netw 2023(1):1–38, 2023).