With the rapid advancement of hydrogel-based flexible electronics, multifunctional hydrogels with an emphasis on environmental sustainability have attracted growing attention. In this work, a starch-based hydrogel featuring a multi-bond network structure—composed of amylopectin, polyvinyl alcohol, borax, and MXene nanosheets—is prepared via a simple, scalable kneading method using a roller machine. The reversible crosslinking from hydrogen bonding and electrostatic interactions, along with MXene nanosheets acting as stress-transfer centers, endow the hydrogel with exceptional stretchability (∼6151%), high electrical conductivity, fast self-healing, and strong adhesion. The resulting capacitive sensor exhibits high sensitivity (gauge factor = 1.1), a broad sensing range (up to 300%), and excellent durability, allowing accurate detection of physiological signals. It also enables Morse code-based encryption of letters, numbers, and punctuation, highlighting its potential in wearable and secure communication technologies. Notably, the hydrogel biodegrades in natural soil within 20 days, addressing electronic waste concerns. This study presents a recyclable, high-performance hydrogel with broad application prospects in flexible electronics, healthcare monitoring, and assistive communication.