I really would like freesync to work without blackouts.
Hi.. one workaround to me and you can try this if you still have this issue.
AMD RADEON setting -> Display -> "create" Custom Resolutions ->
change "Timing Standard" from manual to "CVT-Reduced Blanking" or "CVT"
(both works in my RX470 & LG LCD) -> save .. (all suddenly black gone)