The packaging instructions that used to be on this page applied to the Qt 4 releases and are obsolete.
The Qt 6 releases are built by GitHub Actions, which produce a Debian package, an AppImage, a macOS disk image and a Windows installer for each release. An apt repository, a Homebrew tap (neurosuite/neurosuite) and Nix flakes are available. Packages for nixpkgs, Arch Linux (AUR), Flathub and Debian are planned, see the packaging milestone in the roadmap. If you would like to package the applications for your distribution, please open an issue on GitHub.