Plasma gasification is the cleanest mechanism to convert plastics to energy while rendering byproducts inert, there just isn't much will to implement. Energy output can contribute towards direct air capture of carbon to mineralize, the rest can be from renewables.
You can gasify many materials besides plastic (garbage/waste stream). Filter out metals, brick, rock, glass first. Perhaps site near existing landfills in order to balance the ingest stream between ongoing waste and the waste mine. I have heard the phrase that the landfills of today are the mines of tomorrow, but I think they're more like Superfund sites, all to require remediation in the future at some point (hence the importance of projects that can reasonably degrade these materials into inert byproducts).
https://en.wikipedia.org/wiki/Plasma_gasification
https://netl.doe.gov/research/Coal/energy-systems/gasificati...
https://www.sciencedirect.com/science/article/abs/pii/S03783... ("Plasma gasification versus incineration of plastic waste: Energy, economic and environmental analysis")
https://news.ycombinator.com/item?id=38722984 (u/CptFribble: "I am once again asking you to consider plasma gasification. Here is my standard comment, copied again")
https://news.mit.edu/2021/inentec-turning-trash-into-valuabl... (Control-F "Recycling plastic")
HN Discussion stream on the topic: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
(the art project is fine though)