Metropolitan Opera Radio moved from channel 78 to streaming channel 355 in December 2020. SiriusXM now has 88 channels that are available only online and on the SiriusXM app and connected devices. Among them are many channels that used to be part of the regular satellite lineup, including these:
303 – Venus
330 – Silk
341 – Utopia
708 – Love
710 – The Loft
722 – The Joint
741 – The Village
750 – Cinemagic
Classicalradio.com has an opera channel that I'm certain you will like. It's an online channel – but, unlike SiriusXM, it is free. You can listen on your cellphone while you're driving.
https://www.classicalradio.com/operas