It seems your problem is in temporal anti aliasing (TAA, TSR, FSR, DLSS). They all have this side effect (to varying degrees, depending on the settings).
To some extent, it can be reduced if you enable this flag in the material settings:
You can use other antialiasing methods (FXAA, MSAA), but they either give a worse effect or waste too many resources.
P.S. Apparently, your antialiasing settings in the packed project and in standalone are different, that’s why you see different results.