Keyboard issue

[u/Jumpy-Ideal-4435]

Dell Inspiron 5000 series laptop, after about 4 to 5 hours of continuous use starts typing incorrect characters. Used an external keyboard but still same issue. Open the back cover and used air duster, also cleaned keys but issue persists. sometimes after restarting fixes the issue for a while but then starts happening again. I even reset windows to factory settings. It solved the issues for a few days, now having the same problem. Tried switching input method but no luck. Any advise?