The sad fact is the best use of used plastic is probably burning it to create electricity.
It likely won’t be recycled or reused and even if it is, it’s likely that will only happen once (as recycled plastic is low quality).
So the option is bury it so it can outlast humanity underground or burn it to free up the carbon for hopefully regular consumption in the carbon cycle.
The only way plastic makes sense, then, is if we start using Carbon extracted from CO2 to create plastic.