I tried out numerous audio tagging apps (Kid3, Picard, …) and wasn't happy with any of them. They all try to work with some kind of library system of have a really bad UX (single line input for Lyrics???).
Therefore I decided to build one that is simple, fast, with great defaults: https://github.com/ad-si/Taguar
It's built with Rust's [Iced] and [lofty].
Looking forward to your feedback!
[Iced]: https://iced.rs
[lofty]: https://github.com/Serial-ATA/lofty-rs