From my initial research, it looks like this isn’t practical. libc6 is part of the operating system. Ubuntu maintains fixed package versions for releases, and NVIDIA hasn’t yet released Linux4Tegra with Ubuntu 20.04, so a do-release-upgrade would break compatibility with JetPack, NVIDIA’s SDK for the platform. It looks like L4T based on Ubuntu 20.04 is tentatively planned for Q1 2022:
Any other ideas I could try to get it working in the meantime? At this point I’m thinking that running in a Docker container may be the easiest solution. I saw that Dockerfiles were recently added for building. Have you thought of adding Dockerfiles to run Anki?