Does anyone know if there's an online service I can use/subscribe to that will monitor for flight cancellations?

The scenarios I'm speaking of are something like this (I'm making up the dates/flight #'s, BTW):
AA flight 1234 on 10/4/21 departing at 9:45 a.m.
get cancelled and replaced with say:
AA flight 6789 on 10/4/21 now departing at 3:53 p.m.

Expertflyer apparently doesn't/can't track these types of things (it doesn't count as a schedule change).
They suggest flightstats, but the flightstats website wasn't clear about the flight alerts in this regard.
Now, I'm not expecting anything to know what flight the airline re-booked you on, but I'd like to be alerted when the original flight is cancelled since the email alerts from the airlines usually (IMO) don't work/notify you.

Thanks!