I'm curious how lsr compares to bfs -ls for example. bfs only uses io_uring when multiple threads are enabled, but maybe it's worth using it even for bfs -j1
But more practically, it would be a terror to implement. ripgrep is built on top of platform specific standard file system APIs. io_uring would mean a whole heap of code to work with a different syscall pattern in addition to the existing code pattern for non-Linux targets.
So to even figure out whether it would be worth doing that, you would need to do a whole bunch of work just to test it. And because of my first point above, there is a hard limit on how much of an impact it could even theoretically have.
Where I would expect this to help is to batch syscalls during directory tree traversal. But I have nonidea how much it would help, if at all.