[outsomnia]

Yes, you can do it on a VPS much cheaper.

But this is your outgoing email authorized by DKIM... an attacker can use it to take over most of your accounts via Forgot Password flow. I think it is a false economy to have that depend on a shared VM.

[cubesnooper]

You don’t have to store your DKIM keys on the VPS. I keep my signing infrastructure local, and send outgoing mail over a WireGuard tunnel so it looks like it was sent from the VPS.