The only permanent, "fixed" way to ensure your titles work and are visible to everyone is to earn them through official channels:
Yes. Absolutely.
This is the cleverest part. Miku Client now reads Psyonix’s official title whitelist from the game’s memory, then temporarily adds your chosen title to your local copy of that list. It’s akin to a "man-in-the-middle" attack on your own game data. miku client rocket league unlock all title fixed