The fact that all the stuff dealing with private keys is hard to find or even impossible to export (im not sure if you can access the root seed in Core as you can easily with electrum even you are prompted with it during the setup to print it) is a feature, since having that on display is too risky. So just keep backups of wallet.dat with an encrypted password.

An additional protection to avoid that if someone accesses the file: even if they can use it since they would need the wallet.dat password to transact, they could still see all of your addresses, previous tx's.. I never understood why the password doesn't hide all of that. A workaround is to encrypt the wallet.dat itself, you can use dmcrypt or LUKS in linux, put it inside a compressed file with a password, use a veracrypt container... use SHA256 and a decent password should be impossible to crack. The most important thing is having good memory, that is my problem and I lost access to my encrypted stuff because I cannot remember what the hell I typed as password.