Question Laptop power winks out during boot, even in recovery after a hard reset.

Dec 30, 2019
1
0
10
My laptop was working fine till recently when it suddenly shutdown unexpectedly. Then it would reboot normally. Gradually the reboot worsened while the shutdown was often (and generally while it was idle. No problem when i was watching videos though) the reboot took dozens of attempts to get to login. So i did a hard reset but then It got stuck at cortana screen. After that its been stuck there if 1 in 50 chance i do get that far again.
In all attempts of recovery from boot, the power winks out before its completion.
Its strange, pre hard reset, why did it work smooth after the login only to shutdown when i left it idle? There was no error in any diagnostics that i ran.

Laptop is Dell XPS 15 9570
I should mention its been to germany for repair last month to replace lcd....im suspicious now. My warranty has run out too.
I have done most the recommended power troubleshoot; reseat ram, unplug battery and hold power for 20, run it from just the adapter. No luck. Help would be greatly appreciated, even some understanding of the possible cause.
Thank you