mhwaveedit is a GTK2 audio editor that is surprisingly easy to use. It’s biggest flaw is not having a single window mode, but other then that it is great for quick edits and extremely light weight. I am a fan of it. I am worried that the GTK2 framework is going to be dropped soon, so I hope flatpak can save these apps. (It is still in current repos btw)
Consider making a flatpak of mhwaveedit and hopefully the team ports it to GTK3.