The COVID-19 pandemic had considerable impact on how older adults engaged online, with many using the internet for the first time or relying on family, friends, and peers to perform an activity online on their behalf, a form of internet use known as use-by-proxy. Since we lack large-scale research that compares what factors influence self-reliant internet use and use-by-proxy in older adults during the pandemic, this study seeks to fill this gap. Drawing on resources and appropriation theory, we examine how categorical (e.g., age, gender, education) and resource inequalities (e.g., social, material) shape internet use among older adults as well as the availability and activation of use-by-proxy among older internet non-users. We conducted three binary logistic regression models to analyze survey data collected in 2021 during the fourth wave of pandemic public health measures in Slovenia from a sample of 701 older adults aged 65+. The results show that personal and positional categorical disparities among older adults were significantly associated with their internet use during the pandemic, whereas bridging social capital was the only social resource positively associated with internet use. Conversely, categorical inequalities played a less important role in the availability of use-by-proxy than social resources. In fact, apart from occupation, bonding and bridging social capital were the only positive correlates of availability of proxy users among older internet non-users. Surprisingly, neither type of social capital was linked with the activation of use-by-proxy, which was only associated with two positional categorical disparities: marital status and residential area. Our findings suggest that addressing age-related digital inequalities after the pandemic requires a diversified approach that considers the heterogeneity of categorical and resource inequalities shaping older adults' self-reliant internet use and use-by-proxy.