This paper presents a comprehensive analytical case study of 53 undergraduate courses at a brick-and-mortar Spanish university, examining how Learning Management System (LMS) engagement—defined by LMS design based on the number of unique activities and resources made available by the teachers (opportunities for engagement or intended engagement), course interaction frequency, and daily access frequency (actual engagement)–relates to academic performance and perceived workload. Using descriptive statistics and a Generalized Additive Model, we uncover threshold effects: moderate engagement maximizes both course grades and workload satisfaction, whereas very low or very high activity levels reduce the benefits. Rather than asserting that “engagement does not guarantee success,” our findings surface generative uncertainties, indicating that there are cases where a relationship warrants further investigation. The proposed three-indicator toolkit offers a replicable, course-level method for identifying the trends for optimal balance of the considered indicators within an institution, guiding actions for evidence-informed pedagogical adjustments and further inquiry.