This is not a new proces.
https://en.wikipedia.org/wiki/Gasification
Perhaps it is better balanced to have less of a residu problem but the end result is still CO2 etc... And this from plastics which usually come from oil - ie a solid fossil fuel.
The proces itself is in fact similar to the biocharproces. They say something like 'to turn a onetime use plastic bag into....'. Cough, cough, ..... this at best delayed CO2 release. The main benefit being the elimination of a (technically at least) recyclable waste. if you wanted to sequester carbon, just berry the plastic in such a way that you can extract it later when it is profitable to do so with landfill mining techniques.
Some 15 years ago i was involved in a feasability study with a view to commercialise a technique to turn plastics into diesel and
gasoline. The technique was legally borderline because of the 'lansink rules' which apply here.
https://nl.wikipedia.org/wiki/Ladder_van_Lansink or
https://en.wikipedia.org/wiki/Waste_hierarchy
That meant that the volume of plastics you could feed into this proces was extremely limited and thus commericaly unviable. Even here where we have a population (and waste) several 100 people/sq km.
Last i heared the folks pushing this went to Brazil. Don't know what happened there.
In my view this looks to good to be true. I live in a region where waste incinirators/gasifiers have done their bit to pollute - amongst others - my garden. I'm a sceptic. I can do without any more neighbours with personal waste incinirators.
I think you need a solid quality controll system to guarantee top results al the time. After all how many accidental dioxine releases do you accept ? Who among us has a PHD in chemistry to make sure?