wgpu historically accepts SPIR-V, but the latest version released ~a month ago has moved to WGSL as much as it can in the examples. Have you upgraded yet?
In the game world, it is very common to write shaders in HLSL because of good support on Windows, and then use the tools mentioned above to translate into other shader languages. I explored this for my own work but ultimately settled on GLSL because it allows access to advanced features.
Fans of shader languages should also be aware of rust-gpu, which promises to be considerably higher level; most existing shader languages show their clear lineage to C (through Cg).