How can I enable the device password requirement for all users but not TOTP?
There is no official documented way. You could perhaps program a dummy TOTP-provider which does nothing but it enables this option. Why not use 2FA?
You can request this feature on the bugtracker. But if there is no general interest, this can take some time…
Management doesn’t want us to use Google Authenticator, but they do want the device password functionality.
There are other providers as well: https://github.com/nextcloud/twofactor_totp
Or you use U2F devices.
To program your own TOTP app: https://docs.nextcloud.com/server/11/developer_manual/app/two-factor-provider.html
For business use, you can also consider an enterprise subscription where they can give you help implementing Nextcloud into your environment and perhaps adds some features you desire -> https://nextcloud.com/pricing/