This BananaPi RISC-V router board is officially supported in OpenWRT https://docs.banana-pi.org/en/BPI-RV2/BananaPi_BPI-RV2 and is very affordable. While not as powerful than the Spacemit K1 and having much less RAM, it works rather well and is very stable. Different metal cases available. POE option exist for the board as well.
Orange Pi RV2 is very similar in spec to this star9.com router.
I would have expected some 3dfx based GPUs to be on the top end of the list, considering their rarity, like the 5500 etc, but none are listed...ah D3D benchmark... explains it.
As a long time Alpine user (bare metal, laptop, pi, servers) I can praise the low memory footprint, simple and consistent configuration and up-to-date packages.
Alpine runs great on older hardware. Things that bugged me over the years are the lack of armv5 support (understandably an architecture that is dying) and that their native firewall awall is somewhat limited. Despite being a pleasure to use awall with iptables, it is not capable of nftables exclusive features (eg cake) as far as I understand, yet.
The lack of obscure packages in Alpines repositories is not really an issue in my scenario. Or compiling against musl. Neither is the mentioned DNS over TCP issue.
Using wlroots and sway is a breeze on Alpine and having moved from gentoo > arch > alpine over the years, I am glad Alpine exists. Second choice for me is Void Linux musl and their optional armv5 support via xbps-src.
I hope Alpine will stick around and is not only known to be slim in docker containers.
Orange Pi RV2 is very similar in spec to this star9.com router.