With the release of Unifii OS v2.4.27 on UDM Pro devices, ntopng can now be run natively on the UDM. A podman container is no longer required.
Ntop builds stable and unstable builds that will run on the UDM. See their installation instructions for the Raspian/rPi OS build. The "buster_pi (arm32)" version there is what will install in the Debian (Buster) 11.7 OS on the UDM. (As of 2024-01-16)