HyperPhysics was a fantastic resource even during my studies in the 2010s. Despite the perceived "ugliness" of the format, I found it incredibly intuitive. The "chunking" of the formulas and physics into easily digestible bits of information allowed one to focus on learning one core concept at a time.

I would really love to create a similar website with a more modern stack for my own purposes but don't really know where to begin - so if anyone has any advice here it would be much appreciated!