[mothered]

Personally i don't know how exactly sending email with smtp works. (Even if i have documented myself)

But I think it works like this:
ME --> SMTP --> MailTarget

Correct.

But what if i want more security between myself and my SMTP?
VPN ? Socks5? Both?

Always use a VPN, Irrespective of your computing habits.

For added anonymity, you can encrypt your DNS servers and use Tor over VPN.

Very thanks for your time Mothered ^^

You're very welcome.