The vast majority of plastic is carbon, hydrogen, oxygen chains. You can burn those completely such that the only thing released is CO2 and water vapor (just need a hot enough temperature). A scrubber can easily catch anything that breaks that assumption.
If you do an incinerator and don’t harvest the power, you can even turn it into just a carbon block by filling the chamber with nitrogen and pumping the temp up to 500C. That’ll leave you with carbon blocks and water vapor.
not to create more co2
Plastic decomposes in weird ways that leaving it in the environment is worse than taking it out all together. The reason microplastic is everywhere isn’t because we have been burning plastics, it’s because we’ve been (improperly) burying it. I worry a lot more about a leaky landfill letting it’s pollutants seep into local water systems.
Further, part of plastic degradation is into those more toxic carbon chains and methane. It’s frankly better to just bite the bullet and turn it into CO2.