Been using self hosted mailinabox on a cheap racknerd vps for last 4 years. Zero hiccups.

The trick is to send an email, have it whitelisted a bunch of times. Then it just works.

Once I massmailed by mistake. Google rightly spammed the emails. Had to unspam them and was back within a few days.

Outlook was worst but even that worked.

Its 100% doable