Dell xps Won't Start After a BIOS Downgrade.

I have a dell xps 9570 laptop. I upgraded to windows 11 as it was offered through windows update. After upgrade, my pc went into series of crashes. Everytime, a blue screen would appear and then my laptop would restart.

I deciced to upgrade my bios  but ended up downgrading it to 2018 bios version. The downgrade was successful but after my laptop restarted, it never showed the screen.

When ever I press power button, my laptop keyboard and the charging indicator light lights up and then goes away. It's like my laptop is trying to start but there is a BIOS problem which does not allow it.

I took my laptop to a technician and he took out the bios chip, re-pogrammed it but still the problem is the same. He said he will install a new bios chip in my laptop and see what happens.

Does this mean my laptop's motherboard is dead? I suspect that the problem is with bios chip because my laptop will start but it won't initialize the bios. Any suggestion how to solve it?