I aplaud the write up and recognise that the OP has developed a solution that suits their use case.
Personally I started running my own mail around the same time, but host for several family members at the same time.
I went a slightly different route and pay for a mail filtering service for inbound filtering and outbound relay. All up costs me $90USD per year for inbound and $4 a month for outbound
This has solved most blacklist and outbound mail server reputation issues.
I used to run zarafa till they went commercial. I've since migrated to Mailinabox as a platform. Its pretty resilient. (I've just disabled greylisying and spam detection as I've got upstream MX filtering already) I've also recently been through a MiaB major upgrade - it was pretty simple once I actually read the instructions properly!
Thanks! Yeah that inbound filtering cost is too high for personal use but I was just curious about the outbound relay, which seems to be at most just $4/mo. I think I’ll give this a try, thanks again.