https://www.pcgamer.com/dragon-age-4-development-was-reportedly-rebooted-to-fix-anthem/

According to an extensive Kotaku piece on the developer's internal struggles. Dragon Age 4 development was restarted under a new team as BioWare rushed to prepare Anthem for launch. 

Work on Dragon Age 4 reportedly started in 2017, under the leadership of Mark Darrah and veteran Dragon Age creative director Mike Laidlaw. With the departure of studio general manager Aaron Flynn and Anthem in a desperate state, Darrah was parachuted into the Anthem team as executive producer.