Pathwise regularization by noise for semilinear SPDEs driven by a multiplicative cylindrical Brownian motion

We prove a regularization by noise phenomenon for semilinear SPDEs driven by multiplicative cylindrical Brownian motion and singular diffusion coefficient. The analysis is based on a combination of infinite dimensional generalizations of arguments in the SDE setting as well as careful maximal regularity analysis for semilinear SPDEs and Volterra-sewing techniques.