Phone won't give signs of life anymore

A few days ago my Xiaomi 10 Lite 5G froze and turned off.

The screen suddenly went progressively brighter the turned kind of grey/greenish and pixelated, then the phone turned of and wouldn't give any sign of life.

When I tried to charge it I couldn't see even the little white light that is normally visible near the front camera when charging. An hour or so later I tried to turn it on and it did, but after a few hours the same thing with the screen happened again.

Since that second time it won't show any signs of life. The phone did not come in contact with water, I might have touched it with wet hands (salt water) at some point but that was weeks ago. I didn't drop it either, the screen and everything else look intact. It is pretty hot outside (around 40°C/105°F) but the phone did not overheat and actually felt cool when the issue presented.

I should mention that both times the screen went bright and froze with the phone dying right after I had just connected to a public wifi (once a shop's and the other a hotel's wifi) which made me think it could be a software problem.

I tried holding the turn off button for a few minutes and did the same with both the turn off button and the volume button together. Nothing happens.

Please help me, I've got half my life on that phone.

Thank you