> What if it breaks? Should I backup the recovery key beforehand?

TPM unlocking uses a keyslot in a LUKS container, just like your passphrase does. There are 10 keyslots, so it's not mutually exclusive operation. If TPM doesn't unlock LUKS (as would happen when you put the drive in another device), the bootloader will prompt for a passphrase just like it did before, once entered it will decrypt from another keyslot.