Sorry you got the bad apple Sir. It sucks when your new investment literally goes up in smoke.
Any time you mass produce anything it’s always a roll of the dice as to what percentage will fail prematurely and when it’s made in China those odds increase. But even high end tools have a premature failure rate and although most are caught during testing. Longer tests increase overall product costs and when thousands of units are being produced its more cost effective to replace the few defective units then to increase customer costs to thousands of customers.
I hope you get back up and running soon!
I also see you had the router set to 5 or 6 and suggest when your new router arrives to break in the bearings and brushes.
Start with an end mill tightened at low speed and no load for 1 minute, turn off the router for a minute, turn it back on for 2 minutes at setting 2 or 3 then let it cool for a few minutes again and repeat at a higher setting.
My router when new would noticeably slow down for a second and recover during this process but after running it in the RPM drop went away. The bearings will get hot until fully broken in and that takes a few cycles.