Long-term monitoring of V4641 Sgr with different instruments during the 2024 outburst. From top to bottom: (first) MAXI daily light curve in the 2–10 keV band, obtained via PSF fitting (black), and generated via the MAXI on-demand interface (gray). See Sect. 2.2.1 for details. (Second) Einstein probe light curve in the 0.5–4 keV band. (Third) NICER/Swift/XRISM 1–10 keV luminosity light curves in Eddington units, after removal of the ISM absorption component. (Fourth) NICER/Swift/XRISM 6–10/3–10 keV hardness ratio (HR) evolution. The results in the last two panels come from fitting the time-integrated spectra of the individual ObsIDs in this period (see Sect. 2.2 for more details). The blue and red lines highlight the radio observations reported in Grollimund et al. (2024a,b), and the green line the XRISM and simultaneous Seimei observations.