The latest version of Kali Linux provides both 32-bit and 64-bit images for the Raspberry Pi 4.
J.A. Watson tried both versions and reported on his experience for ZDNet, noting that “Kali is specifically made for security analysis and penetration testing, and is preloaded and configured for that purpose. The combination of the inexpensive and portable Raspberry Pi hardware and the Kali Linux distribution has seemed extremely promising…”
Read more at ZDNet.