I'm pretty sure that I didn't set a password because also I don't want to remember or write anything. I thought letting the software and powering off will freeze the wallet. My friend has told me not to save the seed on any place expect the laptop to secure the crypto and I was pretty sure nothing will hurm the laptop or the ssd.

What is wallet.dat? I couldn't find through Google

I searched on bitcoin core folder and couldn't find that file.