Public awareness of Autism Spectrum Disorder (ASD) has grown in recent years, yet stigma surrounding this condition persists. Building on prior research showing increasingly positive portrayals of ASD, this study examines recent longitudinal trends in stigma and ASD, with a focus on Italian newspapers, and how these were affected by a key event such as the COVID-19 pandemic. We analyzed nearly 3,000 articles published between 2016 and 2025 using an innovative multi-layered Natural Language Processing (NLP) framework to capture multiple dimensions of stigma, including discriminatory language, emotional framings indicative of prejudices, stereotypes, and the thematic contexts in which ASD-related stigma appears. Overall, results indicate low levels of overt stigma and a gradual shift toward more positive portrayals, with only temporary disruptions during the pandemic. Some stereotypes remain, highlighting the need for ongoing attention to ASD representation in the media.