RX 570 + Catalyst 20.8.2 + 1920x1080 monitor
If I want to play some old 1680x1050 HUD-optimized game (such the old STALKERS) I typically use the GPU Scaling+center mode.
It's working but there's a problem: enabling VSync I get an FPS cap that limits the framerate to the monitor refresh rate / 2 (60 hz -> 30 FPS).
Disabling the VSync of course solves the issue but I get the tearing.
Got this problem with custom resolutions too.