The idea is that you can use a wildcard to apply that LSP server to all the filetypes. For example https://github.com/SilasMarvin/lsp-ai and also https://github.com/tekumara/typos-lsp (I already use it on nvim).
Have you tried specifying a highlighting mode regex such as: highlightingModeRegex: ".*",
True, if the server doesn't care for the language id that might work.
"*": { "command": "something" }, It is more easy to understand compared to: "lsp-ai": { highlightingModeRegex: ".*", "command": "something" }, Also because in this way I don't think that works on a new file window.