The ROG Ally X is a Windows handheld gaming PC used for long sessions, frequent charging, and travel-conditions that stress joysticks, battery, and ports. Joystick drift is typically a module wear issue and can be a straightforward repair if parts and labor stay under the threshold.
Battery bulge is higher-stakes: swelling can deform the chassis and threaten the display or mainboard, often making replacement the safer and more economical outcome if damage spreads. Repair is most worthwhile early in ownership for isolated issues (sticks, buttons, fans) when the mainboard and screen are fine.
Replace when multiple inputs fail, when thermal performance degrades (overheating throttles games), or when the USB-C/charging path is damaged and intermittent. Good habits-moderate heat exposure, avoiding constant 100% charge storage, and careful port handling-help delay major failures.