Its the same argument as generating totp using your password manager. Keeping them within bitwarden would be kinda defeating the purpose of 2fa which some people are ok with due to their threat model. If you want them to be seperated, for cloud backups use cryptomator on top of a cloud storage provider that never had your backup of your password manager’s vault. You can generate a passphrase using your manager but instead of storing it within the vault just add it to your emergency sheet, dont forget to add the account credentials and recovery codes to access your cloud storage backup. As for local backups, use any encryption software you like, I like veracrypt. Depending on your threat model you can even use the same passphrase as the cryptomator vault for your veracrypt container. Printed is also nice, I just prefer electronic copies