Downloading unofficial "clients" from unverified sources can expose your computer to malware, keyloggers, or account theft.
Searching for a "Miku Client" to unlock all titles in Rocket League often refers to third-party tools or mods used during the Rocket League x Hatsune Miku miku client rocket league unlock all title work
While BakkesMod is explicitly allowed (because it doesn't unlock paid items or titles), . Using it for titles or cosmetics can result in: miku client rocket league unlock all title work