Many mHealth applications continue to struggle with user engagement and lack features suitable for routine healthcare needs post-pandemic. Although advanced Symptom Checkers (SCs) have recently emerged, they primarily cater to professional rather than general users. This study investigated how interactive graphics modes (2D vs. 3D) and Connector Line Cues (with vs. without) affect users’ task performance, System Usability Scale (SUS) scores, perceived workload (NASA-TLX), and overall acceptance for Symptom-Assisted Appointment. A total of 32 participants were recruited via convenience sampling to participate in a 2 × 2 between-subjects experiment. The results showed that (1) In crowded interface designs, interfaces without line cues sometimes outperformed those with line cues, potentially due to the distance between the lines/labels and their target areas. (2) while line cues aided accuracy (e.g., identifying abdominal regions), they also caused confusion and elevated cognitive load for some users; (3) frequent view toggling in 2D mode increased frustration; and (4) 3D mode was deemed more intuitive for distinguishing between front and back views. These findings provide valuable design references for future interaction designers seeking to refine line-cue usage and 2D/3D labeling.