Quality Education became one of the 17 global goals agreed by world leaders for a greener, fairer, better world by 2030. The ongoing digital transformation in education and culture focuses upon interoperable smart ecosystems in the context of Open Science, LOD, Collections as Data, and AI. The research presented here is focused on how to provide digitally accessible quality education, based on systematization of FAIR, POUR, DEAI sets of principles, WCAG standard and universal design rules. All these have been packed together in our Digital Accessibility (DA) Guide for educators to enable smart ecosystems resources usable by everyone, incl. People with disabilities. We contextualize our recommendations in two domains: life learning platforms and digital cultural heritage. The article examines how universal design principles, WCAG and design-thinking-based-pedagogy together could result in creation of well-perceived and well-structured educational content. The DA Guide proposed, includes W3C recommendations, good practices, and might be strengthened by AI algorithms so that the biggest obstacle for trainers - digitally accessible re-sources for people with visual, hearing or cognitive impairments - to be successfully met. Our research goal is to contextualize the life-learning scope of EU DigiComp Framework for other domains.