1Password 'Environments' and monorepos/collocated deployment configuration

I think you might like varlock (https://varlock.dev)

There is a 1Password plugin that can pull secrets from specific items or load environments. It has the notion of current env (dev/staging/prod/etc) built in, and you can load multiple files, or toggle using functions. You can import files to share config across a monorepo. There is a function syntax to be able to compose values together however you like. There are also drop in integrations for many frameworks, or you can fallback to a `varlock run -- ...` for anything else.

There's a ton more too (built in validation, extra security for your secrets), but I think it will help alleviate many of your problems.