> but I wish there was a middle ground between it and VK

There's WebGPU (probably the best option for teaching), D3D11 and Metal.

And (shameless plug): sokol-gfx tries to find a balance between simplicity and modern 3D APIs:

https://github.com/floooh/sokol

Demos with links to C source and shader code:

WebGL2 backend: https://floooh.github.io/sokol-html5/

WebGPU backend (has a couple more demos which use features not available on GLES3.0/WebGL2, like compute shaders): https://floooh.github.io/sokol-webgpu/