Mock HEALPy maps of the microwave sky simulated using the Skymodel pipeline (see Sec. 3). All Galactic foregrounds and extragalactic components (see Table 1) at the sensitivities, beam sizes, and frequencies of SO LAT and FYST (see Table 2) and the 90% correlated atmospheric red noise between neighbouring channels generated using the noise curves given by Choi et al. (2020a) were included (see Fig. 3).