Glad to help! And, yeah, I’ve heard good things about the Magic Script there, but (with a programming background) I almost find it easier to just write everything myself than to try to figure out what it’s doing. Just to be sure if you haven’t already done so, that’s supposed to go into the “File Naming” page rather than the “Scripting”, so you’re going to need to move it over; the second difference between the two types of script is that taggerscripts ignore any text outside a function or that gets emitted after every function is run, while naming scripts rely on that to determine how to rename the files.
And so you know, you can do whatever you want with your files in Picard. There are three ways your file tags/names affect the database: rating releases or recordings, submitting things via AcousticBrainz, and using the “Submit cluster as release”/Submit file as standalone recording" plugins (I may have gotten their names wrong). The only effect the first has is coloring in some of the stars on the website, the second is designed to handle non-standard tags, and the third will give you the opportunity to fix anything before it’s added. ListenBrainz also receives data, but it’s still a bit difficult to get anything into it without going through Last.fm. Beyond those, nothing is sent back to the database. I personally replace the artist fields somewhat commonly because I disagree that remixes should be listed under the original artist, and then name my files by making everything lowercase, stripping out some of the punctuation, and then replacing the rest as well as the spaces with a combination of underscores and hyphens. Nobody else would want their files looking like that, but because I do, I’m free to mess with them however I think is warranted and it will only ever affect my local copies.