Is there any OS that allows this config?

At least with Linux, if I encrypt my hard drive, I have to enter my encryption password on every login, for some even during boot.

Not sure about Windows. I wpuldn’t be surprised if you can have bitdefender on with auto login.

The password for the hard drive encryption and the system login are two separate things, so, yes, v this combination is easily possible. You’ll have to input a password for system bootup, but not for logging in.

How advisable that combination is is another question entirely.

You’ll have to input a password for system bootup

Encrypted home dir, not the entire drive