AFAIK Ubuntu still ships newer versions. Maybe this is just because it ships new distro versions more frequently, but the end result would still be having newer packages on the latest Ubuntu release vs the latest Debian stable. I'm not an user of either distros though, so I'll wait for someone that actually uses them to confirm/rebut.

Ubuntu is based of Debian testing. You can verify this by comparing the versions of neovim available on the repos.

Debian[1]:

> trixie (stable) (editors): heavily refactored vim fork

> 0.10.4-8: amd64 arm64 armel armhf i386 ppc64el riscv64 s390x

> forky (testing) (editors): heavily refactored vim fork

> 0.12.4-1: amd64 arm64 armhf i386 loong64 ppc64el riscv64 s390x

Ubuntu[2]:

> stonking (26.10) (editors): heavily refactored vim fork [universe]

> 0.12.4-1: amd64 arm64 armhf ppc64el riscv64 s390x

I use Debian stable myself and build neovim from source for this specific reason.

[1]: https://packages.debian.org/search?keywords=neovim

[2]: https://packages.ubuntu.com/search?keywords=neovim&searchon=...