Will Signal ever support this? If not, is there a recommended alternative that is equally secure and does?
Molly can also work along with Signal, if you don't want to loose any history in your primary insall, you can still install Molly on your secondary device and link it to Signal
https://signal.org/
Molly can also work along with Signal, if you don't want to loose any history in your primary insall, you can still install Molly on your secondary device and link it to Signal