Hopefully ECS/fargate will also be supported soon. I tried shifting our CI workers to ARM but it resulted in not being able to use them to build ECS images, which was not great.
Cross-compilation is iffy at best -- too many developers of build scripts don't think about it, and end up not supporting it (e.g. Makefile doing codegen using a binary built during the run for the target arch) or having subtle and mysterious bugs (./configure saves things for the build arch, not the target arch)