That article is utterly unconvincing. It just handwaves the finite nature of our material reality with a very weak appeal to “infinite” human creativity. And then the conclusion is that infinite growth is necessary because there’s no way to change the status quo of wealth hoarding. It’s just apologism for the very worst aspects of capitalism without a single iota of serious thought.
Did you try out all the themes available in your profile? Lemmy comes with a bunch by default but server owners can install custom (“extra”) ones. Lemmy-ui is the place to contribute new themes you want default, but keep in mind there used to be more themes before they deleted a bunch due to maintenance costs.
If you want something totally custom for yourself then a stylish type route is probably the only (outside standing up your own instance) but that and extra themes both will need to be tweaked as new versions of lemmy come out. Lemmy 0.18 for instance involved an upgrade to a new version of bootstrap that mildly broke some theming people had. Nothing prevents lemmy from totally overhauling themes and totally breaking any work you put in.
Depends. If you have a lot of users posting a lot of pictures and you use pictrs out of the box config, then a lot. If you are just running a few users with finite communities being synced then a lot less. The number is going to vary a lot as lemmy grows and gets older so hard to document realistic expectations. But docker images are probably going to take up more disk space than actual contents unless you get quite big. I just threw my PG volume into a tgz to move servers and it’s less than a gig.
Could always just become a nudist. Then you only need to wash towels.