1. FreeSync works as intended
2. Anti-Lag works as intended (it often lowers the input-lag to 1 GPU-frame after CPU-frame in most APIs (DX11 is a little tricky here))
so i guess you have a faulty driver setting or software installed that makes problems.
btw - if you disable FreeSync globally it is OFF and this with ANY resolution
question: are you gaming on a laptop?
ps the equipment needed to show that Anti-Lag is not working as intended is VERY expensive - like 10k$
PC: R7 2700X @PBO + RX 580 4G (1500MHz/2000MHz CL16) + 32G DDR4-3200CL14 + 144hz 1ms FS P + 75hz 1ms FS
Laptop: R5 2500U @30W + RX 560X (1400MHz/1500MHz) + 16G DDR4-2400CL16 + 120Hz 3ms FS