Wouldn't book anything with Aer Lingus at the moment. Almost every flight I booked has been cancelled or rescheduled. I won't book anything with them on the DUB to FRA route until they actually run the flights they sell, then I'll wait a few months (I really get the feeling FR and LH will kick their ass off that route anyway). Every flight I booked in advance DUB-FRA was cancelled by EI. Recent flight to Toulouse was rescheduled to next day so I had to fly DUB-LIS-TLS at three times the cost. I had a flight to LGW with them in three weeks. The return flight was cancelled and they offered me an alternative 7 hours later. I ended up doing an open jaw DUB-LGW and LHR-DUB to get back in time for a business appointment.
If you must be in a certain place (like LAX) at a certain time I wouldn't chance them. They allow you book, then a few weeks before departure they reschedule or cancel offering you a voucher. You then have to source an alternative flight and because its closer to your departure date you will pay much more for your trip so getting your money back from EI for the cancelled flight still leaves you at a loss..
If you're looking for stress free travel you might want to avoid Aer Lingus until at least summer 2022, their schedules are highly unreliable with flight changes and cancellations.