Also using 1Password and I think it’s great. If possible, I would suggest to avoid plaintext secrets in files though. Instead, it is possible to store references to secrets in a dotenv file (example: .env.development):
DATABASE_URL=op://development/database/url
and use op run to inject the secrets into a subprocess instead of storing them in a file:
op run --env-file="./.env.development" -- cargo run