GA uses GPG for encryption but it's neither fast, user friendly or particularly secure (C software from the 90s with huge legacy debt...).

It'd be really nice if you could use a faster, simpler/leaner, modern and reasonably secure piece of software instead for encryption in GA.

I'm not too deep into this but https://github.com/FiloSottile/age looks like an ideal replacement for what GA currently needs GPG for:
It's fast (encrypts /dev/zero at 1.4GiB/s on my machine), modern, simple and designed to integrate well with other tools via the command line. Its creator is the Golang security lead, so the crypto is probably good too

Age seems to be closing in on its "production-ready" 1.0.0 release, so it might be worth having a look at now.