I figured out how to do it manually within the monitor, with Custom RGB settings (please see below)

I'm doing ok with two monitors, and these two settings: 2400K and 3400K

For more details, please see my post titled: Flickering screen, again, with the latest version: f.lux (v4.118) . . . (08/04/20 I accidentally put this in the V3 forum)

Research suggests that f.lux must talk directly to display hardware to work – no remote desktops

I'm curious to see if you get good results also!

2400 K #ff9d3f Standard incandescent lamps . . . HP E272q
255,157,63
(255,157,63)
rgb(255,157,63)
rgb(100%,62%,25%)

3400 K #ffc184 HALOGEN . . . Per f.lux . . . HP 1755 . . . These settings work on the HP 1755, but aren't very orange on the HP E272q
255,193,132
(255,193,132)
rgb(255,193,132)
rgb(100%,76%,52%)