Literally the next sentence in the article:

Digital wallets […] have exploded in popularity but are not captured by Australian payments law.

The article doesn’t bother explaining what specifically the law does.

What software only works on Arch? If anything I see stuff that’s packaged for arch but can be installed from source on other distros without issue.

Ubuntu-only software, on the other hand, is infuriating

It’s a brand exposure exercise… why are you helping the crypto scammers increase their brand exposure?

I host my own, on a server in a data center on IP space owned by a friend of mine. I use mailcow for software.

Ah sorry, I missed that!

This might be more of a hack than you’re looking for, but you could probably install age in termux and put together a small shell script to operate it.

I think the reason you’re not finding what you’re looking for is because another widely agreed upon problem with pgp is that it is a generic encryption and signing tool and those turn out to be a bit of a UX nightmare. Building purpose-specific encryption into other applications tends to have much safer UX, that also tends to be less confusing.

That being said, age may do some of what you’re looking for. I don’t think it does signing but it does do encryption.

Lack of high speed rail isn’t caused by lack of knowledge about how to do it. High speed rail exists in some places, just not the US.