I am not a super experienced coder or anything. But I like thinking about it[1].

The way I've been thinking about it is about organization. Organize code like we should organize our house. If you have a collection of pens, I guess you shouldn't leave them scattered everywhere and in your closet, and with your cutlery, and in the bathroom :) You should set up somewhere to keep your pens, and other utensils in a kind of neat way. You don't need to spend months setting up a super-pen-organizer that has a specially sculpted nook for your $0.50 pen that you might lose or break next week. But you make it neat enough, according to a number of factors like how likely it is to last, how stable is your setup, how frequently it is used, and so on. Organizing has several advantages: it makes it easier to find pens, shows you a breath of options quickly, keeps other places in your house tidier and so less cognitively messy as well. And it has downsides, like you need to devote a lot of time and effort, you might lose flexibility if you're too strict like maybe you've been labeling stuff in the kitchen, or doing sketches in your living room, and you need a few pens there.

I don't like the point of view that messiness (and say cognitive load) is always bad. Messiness has real advantages sometimes! It gives you freedom to be more flexible and dynamic. I think children know this when living in a strict "super-tidy" parent house :) (they'd barely get the chance to play if everything needs to be perfectly organized all the time)

I believe in real life almost every solution and problem is strongly multifactorial. It's dangerous to think a single factor, say 'cognitive load', 'don't repeat yourself', 'lesser lines of code', and so on is going to be the single important factor you should consider. Projects have time constraints, cost, need for performance; expressing programs, the study of algorithms and abstractions itself is a very rich field. But those single factors help us improve a little on one significant facet of your craft if you're mindful about it.

Another factor I think is very important as well (and maybe underestimated) is beauty. Beauty for me has two senses: one in an intuitive sense that things are 'just right' (which capture a lot of things implicitly). A second and important one I think is that working and programming, when possible, should be nice, why not. The experience of coding should be fun, feel good in various ways, etc. when possible (obviously this competes with other demands...). When I make procedural art projects, I try to make the code at least a little artistic as well as the result, I think it contributes to the result as well.

[1] a few small projects, procedural art -- and perhaps a game coming soon :)