What I PERSONALLY have in place is use my own SMTP provider. I chose to use AWS SES. Since IPB is using the AWS platform, it qualifies for their free tier, which is 62K outbound emails per month. (Additional emails are $0.10 per 1K email). My site sends about 15K emails per month, so I have no problem staying within the free tier.
This has allowed me to have outbound sent from my own domain entirely. BUT... this means that IPB won't be able to handle bounces etc. It means I have to manage getting out of the SES sandbox, reputation, etc.
(I was doing this before I moved my site to being cloud hosted. Once I moved to cloud, I just kept my existing already setup mail setup.)