On the left is the DNS server that DHCP sets first. On the right is one it sets second.
This is a mixed machine network (Windows, MacOS, iOS, Android etc).
My clients will mostly pick option number one, but as you can see it's not a guarantee at all.
EDIT. Since lemmy doesn't show kbin images attached to comments https://media.kbin.pieho.me/81/1e/811e8f6bf8aa5e8ea9219ff52d1e61aec8624107ffd11f2a13631d0a1ac29abc.jpg
Linus has repeatedly pointed out that, unfortunately, it works. They make way more money from videos that follow this shitty trend.