Mass Effect 5 is definitely in production, Dragon Age 4.
It has long been mandated by EA that all of the publisher's internal games would utilise DICE's Frostbite engine – suffered as a result – especially in comparison to Mass Effect 1-3, which used the Unreal engine.
Now it looks like BioWare/EA might be considering a return to the Unreal engine for Mass Effect 5. A new job listing for a technical director on the new Mass Effect specifically requires "experience with Unreal Engine 4+" with no mention of any other engines, least of all Frostbite.
Beyond that, industry commentator Jeff Grubb posted a report on GamesBeat where Grubb writes that "multiple sources" confirmed that "everything is on the table when it comes to tech for a new Mass Effect" – including Unreal. Grubb also suggests that the new Mass Effect has barely even entered development yet and won't start properly until 2023, meaning fans shouldn't expect to see Mass Effect 5 until 2025 at the earliest – at which point, Frostbite could look very creaky.
https://twitter.com/JeffGrubb/status/1433923702656155652
Dragon Age 4 will still be using the Frostbite engine, but the Legendary Edition for at least the next few years. Or, y'know, give Andromeda another shot.