I understand why, but you know that 5 weeks is like super early for pregnancy, I don’t mean to be a downer but there is still a 10-20% chance of miscarriage. After 12 weeks(?) I think it drops low enough to not worry too much

Postfix and write a milter (mail filter), you can get them to interact a various points in the mail delivery.

I think most things can be accomplished within postfix

Just sailing? Single hard drive connected to what ever

Hosting stuff you care about? Some form of raid/zfs/whatever with at least 2 discs and a backup plan, also hooked up to what ever

That is the bare minimum. Buy used and expect your needs to change within a month/year.

English, French, maybe German, binary and hexadecimal

Although hexadecimal might be considered cheating