The 64 bit Raspbian supports both arm64 and armhf architectures.
$ dpkg --print-architecture
arm64
$ dpkg --print-foreign-architectures
armhf
The packages built from source code (by method in post #1) have their architecture (arm64) in their names.
dump1090-fa_3.8.1_arm64.deb
tcl-tls_1.7.16-1+fa1_arm64.deb
piaware_3.8.1_arm64.deb