Is there an alternative that isn't directly tied to an apartheid state committing genocide?

Yeah there are countless alternatives (at least here in Germany, but Germans are obsessed with sparkling water so YMMV depending on where you are). A soda maker ain't some crazy technology, it's a CO₂ cylinder, a valve, and something that holds the bottle, in fact, it's so simple, other comments suggest to just build one yourself: https://lemmy.world/comment/13959890

Just make a couple of Google (or preferably DuckDuckGo) searches for "soda maker" or "sodastream alternative" and I'm sure you'll find something that suits your needs.