Signal is removing sms indefinitely due to support issues. Paying extra or installing AndroidPackageKit won't change anything about it moving forward.
If you're using signal for encrypted chat, it's still a good option. If you're mixing sms and encryption, you're SoL. Personally, I'd rather have an app that served both. I'm still trying to find an equivalent option.
@pganssle I don’t have google play services on my devices. Signal offers a direct apk link, as to protonmail and a few other services https://signal.org/android/apk/