Making external display Dell S2722QC work on MacBook Pro

I bought an external display Dell S2722QC the other day, and tried to connect it to my MacBook Pro 2018 via USB C. “No signal detected”. To my dismay, Dell forums were adamant that this display is not supported on Apple devices, and it is not supposed to work. Yet, there were people writing that it did actually work on their devices. I mean, have you heard something as ridiculous as “this display is not supported on your computer”, in 2024? There is no mention of OS or compatible hardware on any store pages of this display, or on its page on Dell website itself, apparently you needed to get this information from some obscure manual, because every normal customer reads those before purchase…

So after googling a lot and trying everything under the sun, from turning it off and on and pressing arcane button sequences with various rituals that are supposed to please the Machine Spirit, I was about to go and return the display to the store, resigning to the fact that I won’t be able to use this display on my Mac.

And then, I recalled an old issue that I had with Linux several years ago - because of the weird “smart” integrated/discrete GPU switching, my display also didn’t get detected.

Solution: System Settings -> Battery -> Options, turn off Automatic graphics switching.

“It just works”.

PS: the monitor itself is like 7/10.