The VkDoom project is an effort to improve GZDoom’s renderer performance with Vulkan, and I’m happy to report that it runs substantially better on Power9 than GZDoom if you have the right hardware for it. Build instructions are essentially identical to vanilla GZDoom, and outside of the lack of a ZScript JIT it runs very well.
DSDA-Doom and Woof are also excellent ports, and run much faster. Have fun Dooming.