Currently, there are more SMTP Configuration options available in the Web-UI compared to environment variables. It would be awesome, if we could achieve parity here. Currently missing is:
openssl_verify_mode
security (so e.g. SSL / TLS / noverify)
More broadly speaking, I would be really happy if more settings (e.g. Company Name, timestamp server, app url, ...) could be configured via environment variables or a configuration file. That would make for easier (or more reproducible) setups which I quite like for selfhosting.