FYI: ctrl + shift + t brings back closed tabs.

While true, the last task is to create a general purpose machine so there’s no puzzle anymore. Only thing left to do is to make it go faster.

Use a hex editor to read binary files. I recommend ImHex https://imhex.werwolv.net/ because it includes all sorts of advanced analysis stuff.

For documents: https://docspell.org/

For media files: https://hydrusnetwork.github.io/hydrus/index.html