2. file a bug against ftp.debian.org asking for the removal of rust-packed-simd on armel/mips64el/mipsel/s390x
That isn't really a workable option. It would just push the problem down the line to other packages. Taken to it's conclusion, solving this through the removal request route would mean removing firefox.
Also because there is only a binary dependency and not a build-dependency the next upload would undo the removal. Be aware that rust in Debian makes heavy use of virtual packages, so tools like "dak rm" and the release teams key packages list cannot be trusted for rust packages.