My new 2019 iMac (2 weeks old, i9, vega 48) started to restart randomly (without any reason and without showing any kernel panic info) and, after increasing the restart frequency to an endless restart loop, it has reached a point at which it does not even turn on. So this new machine is now dead. I have contacted the Apple service and my reseller to ask for a solution. They are working to provide me this solution or repair. I also have a 2010 i7 MBP that is working as the first day (not a single one problem during almost 9 years of daily use. I will use it during this iMac situation is solved. I have a back-up of all my iMac, data but I could not erase the files in the SSD as the computer does not turn on.