I've gotten through the Getting Started section and found it to be quite good overall. A few times it seems to make some jumps back and forth between slightly different setups, which might lead to some problems debugging.

I definitely recommend it to anyone interested! Honestly one of the biggest things it helps with is explaining the setup boilerplate for OpenGL.

Man, this takes me back! I made a Minecraft clone called Mindacraft in Java using LWJGL (the same framework Minecraft uses) about 6 or 7 years ago using this tutorial. I vividly remember this tutorial being the most useful resource for OpenGL by an order of magnitude, and that was with it being written in a language that actually had pointers and buffers! (Using OpenGL in Java is very weird because you have to use pointers and buffers through a bunch of wrapper classes, and it makes things a lot weirder. It's like using unsafe in Rust if unsafe wasn't even in Rust).

Any recommendations on how to use OpenGL from the CLR (.Net/C#) please?

If you want to use the learned knowledge I would recommend to use something like Sokol [0] or use the SDL-GPU API [1]. While Sokol is more higher level both can be used. Otherwise learn opengl is a really good introduction.

[0] https://github.com/floooh/sokol [1] https://wiki.libsdl.org/SDL3/CategoryGPU