The details are fuzzy now, but when I was a teenager I read Tad Williams's series Otherland. It was written in the late 90's and so didn't really grasp how the internet would come to work over time. Its premise was that a lot of the world was immersed in virtual reality worlds, but one group of ultra rich folk had built a secret system that was impossibly realistic, and well, it got weird from there. Still, it had some interesting concepts that really inspired me. Two in particular: • Sellars, and older guru-like figure, had a garden at his home on the military base which was secretly his access to his file system. Eg, each leaf and stem on the plant was representative of files and connection between them, and they could only be accessed by being in the physical space with the plants. • The assassin character had a generative music implant in his head, which allowed him to mentally tweak the inputs on the music playing in his head, triggering swells in the orchestra, or moving from slow to fast rhythm, or changing keys or genres. Not playlists either, but properly generative, with inputs from his own subvocal commands, but also from the environment (eg, light or other sounds) I think there are probably a wealth of future-of-coding ideas in older scifi novels.

Anything that focuses more on the consequences of a novel way of experiencing the computer and less on the mechanical particulars or plot driving effects. It's all about what's ambient.

Vernor Venge’s Rainbows End is an excellent source of inspiration. Highly recommended.