There's already an envelope budgeting tool called You Need A Budget that's well known in the personal finance community, making this naming feel intentionally misleading. This tool is also not how the envelope system works. It's not an envelope per day, it's an envelope per category.
I want to assume best intentions here but this project is raising some major red flags for me and I haven't even looked at the source code. I even kind of wonder if its AI...
I use Lidarr. I know its primary purpose is downloading but if you just never configure those parts, it can do all the renaming, folder organization, and metadata tagging. It uses MusicBrainz primarily, iirc. You can also configure scripts to run it through beets or other tools too.
There's no perfect solution for this because music metadata is a lot more complicated than movies or tv. But Lidarr gets pretty close to set-and-forget.
I've also tried MusicBrainz Picard with pretty decent results but I found it sort of suffered from the problems you described for your current system.