Tried running the DX11 to Vulkan with DL2 (and my old OCd RX 470, dont regularly play DL2 wit this card) and got about a 10-15 fps boost even without FSR, but
HIS RX 470 IceQ X² OC 8GB < RX 470 Series < Desktop Graphics < Products | HIS Graphic Cards
Cannot Start Game When Vulkan Enabled - RX 470 Ubuntu 16.04 · Issue #237 · ValveSoftware/Dota-2-Vulkan · GitHub