To add on to the conversation, I also read up about this to figure out why there are so many folders like this.
Like the person in the other thread mentioned, rpgmaker is made with NW.js, which is based on Chromium and Node.js. Chromium in particular has a User Data folder where it stores info that would be useful for a web browser, which is mentioned in the Chromium documentation:
You must be registered to see the links
Also since Chrome obviously uses Chromium it has its own User Data and Default folders (which the docs mention is also located in Appdata/Local), and have a ton of files and folders, some of which are the same files seen in the other User Data folders that many people are worried about.
Also in the NW.js documentation it mentions where the data path for an NW.js app is located:
You must be registered to see the links
Just like Chromium, it's also located in Appdata/Local which likely means this was inherited from it. However, it has a <name> variable in the file path, which the docs say is located in a package.json manifest. If you look in any rpgmaker game folder where the exe for the game is, there is also a package.json file, and when opened with any text editor, a web browser, or even Notepad, it lists a few name/value pairs. The first in the list is almost always "name", and whatever value it has is what NW.js uses to name the data path.
For example, in some rpgmaker games that I've installed, the "name" value is "rmmz-game", which is probably a default name for rpgmaker MZ projects and explains why I have a rmmz-game folder in my Appdata/Local file path. Most games have empty quotations, which defaults to the file path Appdata/Local/User Data, some have random text which creates the Appdata/Local/<random-text> folder, and some actually have the name of the game, which also explains why game titles are in Appdata/Local.
This is why I don't think the existence of these folders is anything to be worried about, it's just files and folders that are made from rpgmaker games (unless the game was tampered with to include malicious files, like this game was during that time period). Also people worrying about the User Data folder seems to occur every now and then, since this was also brought up in the
Daily Lives of My Countryside thread over a year ago.
Also feel free to correct me on any of this, I'm just trying to give myself and others some form of peace regarding these folders.