I have good news: Libreboot just got a big update. Not yet a new release, but Libreboot's build system now uses the latest coreboot revision on most boards; GRUB and SeaBIOS payloads have also been updated to newer revisions.
It is announced here:
https://libreboot.org/news/update202308.html
I would ask all those interested to provide testing, based on this. Information is given, on the announcement.
There *will* be two more Libreboot releases, this year - possibly three. I'm starting a massive push, as of today.