Not sure how it might play with your moderno 'O' or 'X' ring chains, but a cheapo chip brush and some diesel or kerosene with an old cookie baking sheet underneath to catch the drippage, would help first rinse off those grits, which are the real chain killer. What you might then slop on is kind of a matter of taste. I just use old filtered gear oil on my old style Plain Jane chain, as recommended in that previously-referenced FortNine video, it turns out. Most every time I come back from a jaunt, I just slop a bit onto the easy-to-reach bottom run of the chain. I've put about 6,000 miles on it with just one notch taken up in its snail-shaped adjuster so far...but then I do almost no off-road or gravel riding.
I should mention that I've read somewhere or other that WD40 will do no favors for the 'O' or 'X' ring seals in modern chains, and might even harm them, and while it's not really a sturdy enough lubricant on its own for the old style chains, it can be used to good effect as a sort of pre-lube cleanser to help blast off the grits, if that's what's handy. Now and then I'll also give that little pulse air doodad on my header a little squirt while it's still kind of hot, and it sort of vaporizes nicely up into the nacelle to help keep the electrics happy and any corrosion within the headlamp shell at bay.