Occasionally I'll get hit with a few unwieldy conflicts. Usually it's one or two lines, and always a whitespace issue because someone's code style just has to be different.
Yes. You can use an existing SMTP server (gmail [legacy app mode], yahoo, microsoft, etc). One thing to keep in mind -- if you decide to go that route don't use your personal account because the address might be exposed in the mail headers. Create a dedicated account and use that instead.
lemmy.hjson
email: {
smtp_server: "smtp.example.tld:[port]" # port 25, port 587, etc
smtp_login: "username"
smtp_password: "password"
smtp_from_address: "noreply@example.tld" # or account_just_created@example.tld
tls_type: "tls" # or starttls
}