Auto on off issue.

Lenovo legion y540 i7 9750h with rtx 2060

I'll explain my issue in a sequential order.

1. My battery was swollen like a year ago. I didn't replace it i just removed it.
2. After removing it and using for a year, whenever i plug my laptop to power it instantly turns on n boots without me pressing the power button.
3. 3 weeks back my clocks stopped working properly.
4. After 2 or 3 days when i turn on my laptop the power led blinks and it does turn on but no display, the fans run n abruptly stops.
5. I tried replacing the CMOS.
6. I tried to check if my ram was the issue(wasn't ).
7. I went to the service centre and gave it to them.
8. They said they tried a few but the issue wasn't resolved.
9. They said that the laptop was usable but sometimes rarely it randomly offs.
10. They said that they replaced the capacitor, tried some spare power components, checked the chipset.
11. When i asked them today they said that it needs a motherboard replacement. :)
12. I have no idea what to do.