That is an additional fact which you did not include in your OP and which changes the situation.

With the cancellation causing a 4-hour delay, you are entitled to a reroute which would include cancelling the segment without penalty. It won't likely result in a refund of much if anything, but you can't be charged anything.

Neither I nor others here are joking. It is <2 hours drive time to SAN and perhaps less depending on where you are headed (presuming not the airport). Depending on your means and your preferences, use a land transfer and you will be in SAN 2 hours after departing LAX rather than having 4 more hours in a rotten lounge waiting for a rotten micro-haul aircraft to sit on the ground for a 15-20 minute flight.