<humor>Why so much hatin' here? I thought the HN crowd would love someone who had their own email server.</humor>
Obviously if you are of .gov employ, you should not do this.
I do have my own email server, cloud server, etc hosted on DO and don't work for the government. But I have two phones, one for work and one for personal and do not mix work/personal data.
Relevant mail-in-a-box link https://mailinabox.email/