Not addressing your question, but FWIW:

Mail is the one thing I eventually caved on and offload to Microsoft. It's an uphill battle keeping your mail out of Spam folders. You setup DKIM, SPF, etc. according to the latest spec, and at the end of the day, the MS and Google still drop your mail in spam. They simply don't care.

Second, the forces and money keeping MS above legally bound 99.9% uptime tower in comparison to any one person's own resources. Is your daily driver even operational 99% of the time you use it? We hackers can't help but to tinker, so I suppose not.

MS has teams of engineers paid specifically to keep the thing running and NOT tinker. At only ~$10 / month that's a no brainer.