Many of the things are "Fix #NNN` which means fixing a specific GitHub issue which usually has more information to it or has comments in the code, etc. There are many "Fix typo(s)" commits because I (and others) make a lot of typos; these are usually trivial/single-line fixes. Then it comes to the rest of "Fix ..." commits which are pretty much 1-2 line fixes of minor bugs; with large bugs having multi-line commit messages and many with huge comments within the code to explain everything.
Your metric of the quality of commit messages is not a bad one depending on the codebase, but it cannot be used blindly without knowing how that codebase operates. Especially comparing a mostly centralized codebases (like Odin) to very GNU-style decentralized codebases (all of the examples you gave).
A commit message has a function which is directly applicable to the craft of programming and not something auxiliary like the aesthetic properties of a shed used by the bicycle commuters. Though in this case I would disagree with the GP since “Fix <thing>” might be a good enough commit message template.
As the project grows in contributors, the commit log gains value
According to GitHub, there are 132 contributors. Probably most of them were one-off drive-by PRs, but nonetheless, it's definitely not a one person project anymore.
Take a look at the commit histories of the other projects I've linked. Their commit messages are much more elaborate.
<thing>
Sadly, Odin doesn't seem to pass the test. It's full of commits labeled with just "fix <thing>": https://github.com/odin-lang/Odin/commits/master
A few examples of projects with better commit messages:
Linux kernel: https://github.com/torvalds/linux/commits/master
gcc: https://github.com/gcc-mirror/gcc/commits/master
Perl: https://github.com/Perl/perl5/commits/blead
Wayland: https://github.com/wayland-project/wayland/commits/main