Yes what you're looking for is the dots to display (from left to right) red red nothing
If the outlet is grounded properly it would lead to a PSU issue.
Not sure what country you live in but grab one of these, for your outlet type, and confirm your outlets are wired properly.
If they are it could be a psu issue.
The case was released in 2018...
Thermals in the case are fine. By not adding the side panel you are not directing airflow from the front of the case to the rear of the case.
You could remove the front door completely and expose the mesh front panel.
FD has a list of compatible accessories https://www.fractal-design.com/products/accessories/ anything else would be custom.
If the liquid metal is between the die and the heat sink you do not need to reapply it if you haven't taken the CPU out of the socket. Intel socket does a good job of holding the heat sink on the die.
Clean the paste off your heat sink top and apply new when changing coolers.