To run a development version you can build from [the VCS package in the AUR](https://aur.archlinux.org/packages/neovide-git).
This can be built and installed using an AUR helper or [by hand in the usual way](https://wiki.archlinux.org/title/Arch_User_Repository#Installing_and_upgrading_packages).
To build from a non-default branch you can edit the PKGBUILD and add `#branch-name` to the end of the source URL.