I use smartgit it serves me well: https://www.syntevo.com/smartgit/

And it has all 3 of your criteria as far as I can see.

I recently watched downsizing, whose main topic was overpopulation and I remember a time where there were some papers on that the earth will soon be overcrowded and I'm very happy that this simply won't be an issue for us in the future anymore.

I also was playing around with that idea, but wasn't sure if I actually want to fund projects or art and architecture around it.

Basically paying artists to draw their vision, because that would be like advertising the Solarpunk idea.

Der Transrapid war kein Vakuumröhrenzug sondern eher eine Magnetschwebebahn. Also sowas wie in Japan und China täglich zuverlässig Menschen bereits transportiert anstelle ein Luftschloss zu sein.