Freesync on DVI-D monitor black screen BENQ

EDIT: I rewrote the post, so it's easier to actually read it.

AMD recognizes my monitor as Freesync-enabled BUT it will only output black blank screen, forever.
I'm using DVI-D on GPU's and monitor's side. Using any adapters will make my monitor not recognized as Freesync capable in the first place.

Monitor: BENQ G2220HD, only VGA and DVI-D (Dual-link I suppose). The display scales everything on its own, which might be the source of the issue.