I own apartments, and sometimes have Section 8 tenants! When I have an inspection, the inspector uses a classic polarity tester to twist and wrench each outlet. If he tester flickers at all (continuity break) I have to replace it! (If they weren’t shot before they test them they definitely are afterwards.) Now I just replace them all.
And yes, you can replace a 15 amp outlet with 20 amp one. It makes thing safer! I often do it to “high stress” areas such as kitchen counters!