It appears Instagram and FB owner Meta holds the trademark for "X" as it relates to "online social networking services... social networking services in the fields of entertainment, gaming and application development..." https://tsdr.uspto.gov/#caseNumber=87980831&caseType=SERIAL_NO&searchType=statusSearch via @[email protected]
Trademark Status & Document Retrieval

@taylorlorenz marvellous. They can fight for it in their cage match.
@taylorlorenz @defcon Ha, you made me LOL!