Get a domain, get webhosting that includes an email server, now you can generate unlimited emails from whichever program you want. And the email reputation will probably be the same as with this service.

Any hosting services with email you'd recommend? Are you talking about a service like Fastmail or something?

I am using a webhosting plan from Netcup for my email:

https://www.netcup.com/en/hosting

I got it during a sale so I’m paying 1€/month for 1 domain and 40 GB of storage.

Thanks I’ll check into this as well. One of my requirements is being able to generate addresses programmatically, not sure if the NetCups service supports that or not. But either way, that’s a good deal!

They use plesk and that seems to have an API so maybe you could do that. I just use a catchall email address to receive and use one to send. To send from more you need to create users or add addresses to users in plesk so you would probably need the API.

maybe tangentially related but i've found cloudflare's email routing useful to just send emails to blah@customdomain.com sent to blah@myemail.com. i'm not sure if it's limited to domains registered with them though.

Thanks, I’ll have to check that out. All my domains are with them anyway so this could be just what I was after!