Is a dual cpu mobo worthwhile for a homelab server
9 times out of 10, no.
In a world where a couple cheap NUC/Mini PCs loaded to the gills with 64 GB of RAM each is more than enough for a lab, dual processor builds are mostly for bragging rights and folks who don't have to contribute to the power bill 🥵
There are a lot of things that are fun to lab. Email is not one of them, seriously— leave this to a cloud provider.
The day Exchange stopped being one of the things I had to manage was a good day indeed 😅