I know a mononymous person (who has one legal name, no separate given and family names) and he said something along the lines of using one ofNameName .Name 'Mr NameName NameNFN Name (u2018No First Nameu2019)until he finds a variation that is accepted.Ah, found where I might have read it - one of the top comments on Page on reddit.com, by u2018saizaiu2023 (Sai).Another result is that some departments/organisations/sites consider his name to be a family name, others consider it to be a given name.