Wellderly Brain is a randomized, direct-to-participant trial evaluating whether a virtually delivered, multidomain lifestyle coaching intervention can favorably impact plasma biomarkers of Alzheimer's disease (AD) in adults aged 60-80 with APOE4 positivity or elevated polygenic risk. Participants are recruited through 23andMe and enrolled via the MyDataHelps platform. Following genetic eligibility screening, 1,200 participants will be randomized to either a digital lifestyle coaching arm (UCardia) or an education-only control arm. The intervention consists of 16 virtual coaching sessions delivered over 52 weeks. All participants will wear an Oura Ring for continuous health monitoring and provide dried blood samples at baseline, 6 months, and 12 months for plasma p-tau217 and proteomic profiling via the NULISAseq CNS Disease Panel. Saliva samples will be collected for epigenetic aging analysis. The study duration is 14-16 months per participant.