Robin double-phase problems with singular and superlinear terms

We consider a nonlinear Robin problem driven by the sum of $p$-Laplacian and $q$-Laplacian (i.e. $(p,q)$-equation). In reaction there are competing effects singular term parametric perturbation $\lambda f(z,x)$, which is Carath\'eodory $(p-1)$-superlinear at $x\in\mathbb{R},$ without satisfying Ambrosetti-Rabinowitz condition. Using variational tools, together with truncation comparison techniques, we prove bifurcation-type result describing changes in set positive solutions as parameter $\lambda>0$ varies.