If you don't want to invest in getting your contacts on Signal, you can try OpenBubbles. It gets iMessage on Android devices and works fine.

I highly recommend switching to GOS, it is wayyy better than iOS UX-wise and obviously better privsec and freedom.

One thing that I had to do when I first got GOS, to get a better experience, was find all the Open Source apps that I needed. Otherwise, it looks rather bland and the apps are mid. Once you find the right apps and launcher, everything works much better.