65 C is... not a high temp. The variance you're describing is not at all surprising to find between two different systems, nor a cause for concern, assuming that is the normal/typical operating temp for the 2060.

If you were talking about idle temps in the 80s, there might be cause for concern... but the full-load temps you're describing are lower than some people's water heaters are set to; well within tolerance (and even spec) for most GPUs.

Blow the dust out, maybe add a case fan or adjust the case airflow... If it were me, I wouldn't even worry about it, but if it bugs you that much, maybe clean off the stock paste and apply some premium stuff... just don't expect amazing results, because (in my opinion) you're freaking out over something that isn't worrying in the slightest.

To be completely honest, some people who would kill for full-load temps in the 60s... the high end of the "normal operating range" for modern GPUs is 85+.