do a reset, get rid of everything and start over. (it's better to just do a clean install, get rid of the additional partitions created during upgrade)

it's a laptop. it's common to have cpu going up until 80c+ under load, room temperature. it's fine as long as it's not over 85c. (unless you were saying that 60 to 70c is the temperature when the computer is idle)

the thermal paste cannot do magic in most cases. btw how did you apply as5? you should apply it to heat sink (spread a thin layer of as5) and cpu die (vertical line, recommended by as5 manual). it also needs curing time of about 200 hours to achieve its optimal state.

No need. go for clean install first. Some apps must be sucking up your CPU performance.

oh that's not good. what is your laptop brand and model? most laptops should do +- 60c when idle at room temperature. (mainly depending on cpu models. for instance, my 4900mq is avg. 58c at idle, on top of notebook cooler, oc'ed to 4ghz btw)

like others pointed out, it's better to check if a reset or clean install solve your issues. a laptop cooler is optional normally. all you need to do is to lift the laptop up a little at the back to give space for air flow.

although it should work the same, i am not really familiar with amd systems sorry.