This may not be the best advice but this is what my computer struggled with as well when I first got it 'booting.
I let it run with that power cycle for a couple of mins (where it keeps turning on and off) until the CPU fan would finally kick in. Immediately found the S.M.A.R.T fan function as the culprit (in ET6).
My specs are almost the same as yours. Good luck with your issue, hope this helps!