Ok, I figured it out. To make the changes permanent after changing the ROOT, I save the file "auto.example.test.conf" without the "auto" prefix, i.e. ""example.test.conf". So next time I reload apache, laragon automatically deletes the auto file and keep my new file with the custom DocumentRoot.
Just posting this here in case anyone else stumbles upon this.
I can't say it enough, but thanks Leo Kho so much for this wonderful piece of software!