This study presents a novel bio-solvolysis process for the chemical recycling of complex poly(ethylene terephthalate) (PET) waste using biobased monoethylene glycol (BioMEG) as a depolymerization agent. The process was tested on five difficult-to-recycle PET waste streams, including multilayer trays, coloured bottles, and postconsumer textiles. The PET was depolymerized into bis(2-hydroxyethyl) terephthalate (BHET) monomers with a conversion rate of 91.3–97.1% and a BHET yield of 71.5–76.3%. A monomer purification process using activated carbon (AC) was developed to remove color and reduce metal content, resulting in a significant increase in BHET whiteness (L*) from around 60 to over 95 and a reduction in zinc content from around 200 to 2 mg/kg. The purified BHET monomers were analyzed using FTIR, DSC, and $ ^{1} $ H-NMR, showing high purity with up to 99.5% BHET content. The study demonstrates that the biobased glycol achieves the same PET conversion and BHET yield as fossil-based glycol, while reducing environmental impact. The process offers a sustainable solution for the chemical recycling of complex PET waste, enabling the production of high-purity monomers suitable for food contact applications.This study presents a novel bio-solvolysis process for the chemical recycling of complex poly(ethylene terephthalate) (PET) waste using biobased monoethylene glycol (BioMEG) as a depolymerization agent. The process was tested on five difficult-to-recycle PET waste streams, including multilayer trays, coloured bottles, and postconsumer textiles. The PET was depolymerized into bis(2-hydroxyethyl) terephthalate (BHET) monomers with a conversion rate of 91.3–97.1% and a BHET yield of 71.5–76.3%. A monomer purification process using activated carbon (AC) was developed to remove color and reduce metal content, resulting in a significant increase in BHET whiteness (L*) from around 60 to over 95 and a reduction in zinc content from around 200 to 2 mg/kg. The purified BHET monomers were analyzed using FTIR, DSC, and $ ^{1} $ H-NMR, showing high purity with up to 99.5% BHET content. The study demonstrates that the biobased glycol achieves the same PET conversion and BHET yield as fossil-based glycol, while reducing environmental impact. The process offers a sustainable solution for the chemical recycling of complex PET waste, enabling the production of high-purity monomers suitable for food contact applications.