An RX 550 is a low end GPU from 2017. If you've already set everything to low settings, then that's all the performance you can get.
Sorry to say, but you need to upgrade.
Gpu is not the only thing that runs your games smooth, VOTV is kinda CPU intense too and its made on Unreal Engine 4, maybe you see lo-fi textures and think the graphic is "HalfLife level" but it's not, it has a lot of advanced lighting/shadows and a lot of physics calculation too. Being in alpha stage, consider that the whole game is just poorly optimized for obvious reason.