Change ib.cancelMktData(tick_id) to ib.cancelMktData(instr) Based on ib_insync source code:

 def cancelMktData(self, contract: Contract):
    """
    Unsubscribe from realtime streaming tick data.

    Args:
        contract: The exact contract object that was used to
            subscribe with.
    """
    ticker = self.ticker(contract)
    reqId = self.wrapper.endTicker(ticker, 'mktData') if ticker else 0
    if reqId:
        self.client.cancelMktData(reqId)
    else:
        self._logger.error(
            'cancelMktData: ' f'No reqId found for contract {contract}')