EA's titles usually run on Frostbite, the engine some attributed the poor workings of Mass Effect Andromeda to, but it appears Mass Effect 5 might be different.
Mass Effect Andromeda was a failure for the series in every sense and a lot of blame flew all over the place, targeting just about anything you could put a finger on. This included the Frostbite engine, which received criticism for other shortcomings too and players were growing weary of all EA titles being apparently forced onto it.
This proved to be partially true in the past as the company didn't directly state all of their studios have to develop on it but the studios did have to cover the licensing cost of using a different engine. Respawn Entertainment paved the way with their own gambit through Star Wars: Jedi Fallen Order which proved to be a success and now BioWare might follow in their footsteps.
A job listing for Mass Effect 5 Technical Director noted that experience with Unreal Engine was required so putting two and two together isn't too hard. On top of that, the fabled ME trilogy was all created on Unreal and some of BioWare's biggest failures - Andromeda and Anthem were made on Frostbite.
Hopefully, going back to UE might herald at least a partial return to BioWare's shine but considering all the key figures that are no longer at the studio, this might just be a fan's wishful thinking.