The env.php file has been replaced by the .env file. All the email settings are in there. Return the config.php file to its default state.
In addition to the link kindly provided by @DisposableHero , your hosting panel should provide an Email Accounts area with valuable info.
If your hosting provides cPanel, have a look at this article to set up SMTP
https://cpanel.net/blog/tips-and-tricks/setting-up-and-troubleshooting-smtp-in-cpanel/
I would suggest updating any phpVMS v7 sites you help with to the latest dev build, available in the #v7-releases channel of the phpVMS discord.