Yes, this will uwuify your text at high speeds. It reached 2.3 GB/s on my 8-core macbook pro, while uwu-ing the first 1 GB of english Wikipedia. This Rust command-line tool takes advantage of SSE4.1 SIMD vectorization and multithreading to be almost as fast as simply copying a file. Installing it is simply cargo install uwuify, assuming you already have Rust installed. It is on crate.io:
https://crates.io/crates/uwuify