

OrgAbuseHandle: ABUSE9107-ARIN
OrgAbuseName: ABUSE
OrgAbusePhone: +1-313-516-8908
OrgAbuseEmail: abuse@hostodo.com
OrgAbuseRef: https://rdap.arin.net/registry/entity/ABUSE9107-ARIN
They have options. No idea if they actually do anything for the reports, but it’s worth a shot.

My ISP offers unauthenticated SMTP for their customer addresses. It’s pretty heavily rate limited, but well enough for the occasional status email my system throws out. At least around here they are pretty common for residential customers, so that might be an option.
Other possibility is to set up SMTP relay to your network and give it credentials to an actual email account (with SMTP support, which isn’t granted these days). It can take in emails from your network without credentials and throw them to the internet with your account. It’s pretty simple to set up, search for postfix + smarthost. Added bonus is that you can read the replies to that address too via your email provider services.