engineering wise I can't see why it wouldn't be possible to selectively genetic-engineer some kind of plant or algae or something that sucks up tons and tons of carbon that you can then sequester manually by compressing it into, I don't know, artificial peat or something.

I have no idea why massive factory growing operations for produce aren't everywhere. Every city should have one by now, growing produce locally and shaving down the price of transport and waste to almost nothing.