If you're doing sequential I/O, you will hardly be able to be faster than std library - it is synchronous, goes directly to the operating system, which does read-ahead. 40+ years of OS design was meant for this. io_uring can't beat it either, it's just too ubiquitous of a usecase to not be hyper optimized.
If you do any non-sequential processing, let's say a database, then you can see standard library show its weaknesses - feeding the operating system with multiple requests becomes more efficient than waiting for each request to finish in the synchronous std case.
