I use BeyondPod (BP). It has a lot of minor bugs in the BT connection, but nothing that prevents it from playing. I almost never see the timeline progress bar on the car display. I sometimes do see the graphic for the current podcast along with its title. More often it just says "Unknown title" on the car display. Mind you the phone itself is far more helpful!
On the few occasions that I've used Android Auto (AA), it has been really awful. I don't know if the problem is AA or BeyondPod. I never see a timeline. Half the time I don't even see BeyondPod as a panel in AA. When I select the headphones icon, I can get to BP, but there's not much to see. AA is truly awful, outside of the podcast experience. I don't know if the problem is the AA app on my Moto G5s+ or if it's the AA installed on the car.