Within the CC domain, the CVS scheme was pioneered by Coriani and Koch for computing core-excitation and core-ionization energies. Since then, the CVS strategy was used in several CC-RSP and EOM-CC frameworks, enabling the modeling of XAS, XPS, XCD, and XES spectra. 11, The theory was further extended to higher-order properties such resonant inelastic X-ray scattering (RIXS) cross sections. 11-13 Similar to 2PA, RIXS is a two-photon process; RIXS moments are also formally given by sum-over-states (SOS) ex-pressions within the EOM-CC expectationvalue framework. In practical calculations, the SOS expressions are recast into closed-form expressions using first-order response wave functions. The RIXS response calculations for these wave functions are affected by their coupling with the continuum, and CVS has been recently adapted to deal with this issue. The limitations of straightforward application of CVS and possible extensions have been discussed in Ref. 13, giving rise to series of approximations such as CVS-0, CVS-uS, etc. (see section 2.3 below).