I'm comfortable opening up a device like that and replacing parts if necessary, so I would buy one under the right conditions.
Consider:
- Is it a genuine DualSense, or a counterfeit?
- Does the seller have a reasonable return policy?
- Is the price low enough that you would still be saving money (vs. a new one) if you have to buy a new battery or stick?
- Calibration can compensate for mild stick drift, avoiding the need for hardware repairs.
Related:
https://www.ifixit.com/Wiki/How_to_Identify_PS5_DualSense_Controller_Version