doing a bit of googling myself it seems you need to use the AMDGPU drivers instead of MESA. see these both for more info and a solution (latter) in getting amdgpu to run: https://www.reddit.com/r/linux_gaming/comments/hhs7lo/r7_260x_vulkan_on_ubuntu_2004_doesnt_work/ and ...
Video card (GPU)ATI/AMD Radeon HD 2600/3600 Nvidia GeForce 8600/9600GT DirectX 11 compatible Sound (audio device)DirectX Compatible Tom's HardwarebenchmarkedDota 2's performance and concluded that integrated Intel or AMD graphics should be enough for 30fps at 1920x1080 on low settings. ...