> Micro and nanoplastics are also a problem that urgently needs to be addressed.

Bio-plastics won't do this automatically. You can make today's polymers from biomass feedstock. Those will have the exact same micro/nano plastic problems.

You can also make polymeres, that are much more bio-degradable, with the associated particulate matter decaying instead of accumulating forever - but you could make those from crude oil just as well, and those degradable polymeres bring an entirely different zoo of problems with them.