I had all the time in the world in my last job to develop a chain cleaning regime....
Bear in mind I work in a workshop, have high pressure airlines etc etc..
Chain off, wipe, blast with high pressure airgun, spray with WD or similar, blast with airline again...all this probably took minutes, maybe 5. The black gunk flows oit.
Then soak in a tray of oil...half an hour maybe while I did something else.
Hang on a nail over the tray for the rest of the day to drip all the excess off.
Thoroughly wipe, wipe again, wipe ahain. Fit to bike, wipe again.
In all, I probably spent 10 minutes on the chain each time, split up over the day.
I occasionallycleaned it with high power degreaser then airline, dry, driptray etc as above.
During the winter, this seemed particually neccessary.
Did my chain last any longer.....no. IME, with hindsight, its a waste of time spending too much time cleaning chains. It doesnt extend mileage in chains at all or its insignificant.
Ive long since come to the conclusion a chain is a consumable, wipe it, oil it sparingly, spin pedals, leave it a while then wipe thoroughly.
A good rag, a drop of oil on each roller and a good wipe....my chains las.t just as long as they ever did