Is there a good “secrets manager” or “encrypted information manager” that’s free (preferably also open source) or quite cheap (not subscription based), is multi-platform (including mobile) and supports auto-fill in other applications (especially browsers)?

Password managers with password generators and 2FA code generators are ok for work related use, but they usually may not cover other pieces of information, like credit/debit cards, software licenses, identification cards, hardware/appliances, etc. Adding custom fields in each entry by oneself isn’t a great option. Perhaps it’s not a great idea (even with a very strong master password) to put all the information in one database, but I see value in being able to store, retrieve and auto fill different kinds of information (even if some may seem too complex to define in a generic schema).

I already tried Bitwarden, but it covers only passwords, cards and identities (plus secure notes).