Notes on linear elliptic equations with $L^2$-gradient perturbations and singular zero-order coefficients

In this paper, we study the existence, uniqueness, and quantitative estimates for weak solutions to linear elliptic Dirichlet problems of the form \[ -\operatorname{div}(γ\nabla u)+\langle \nablaϕ+\mathbf{H},\nabla u\rangle+(c+α)u=f \quad\text{ in }U, \quad\; u=0 \quad\text{on }\partial U, \] where