I use a wireguard tunnel and port forwarding from a vps to a mailinabox instance serving mail for my various domains. If you have your SPF/DKIM/rDNS set up correctly, it’s not too bad with respect to management and mail delivery, plus you don’t have to trust anyone with your data. As far as other mail servers are concerned, your VPS IP is the only IP they see. I pay $10/yr for the VPS