K-9 mail… isn’t supported or being developed any more.
That’s not true. They make frequent-enough releases, they post monthly progress reports, and they are actually going to become Thunderbird’s Android version.
Having said that, I almost switched to FairEmail because K-9 lacked support for some sort of authentication measure (which I no longer need), but that wasn’t because K-9 stopped development.
https://en.wikipedia.org/wiki/List_of_United_States_presidential_assassination_attempts_and_plots#Assassination_attempts_and_plots
You’re correct. You’ll notice every president in recent history has multiple assassination attempts listed. The bulk of them don’t go very far.