I think I have resolved my issue by changing AVRCP to 1.3 on my device (OnePlus 7 Pro) It was set to 1.6 and this and other options (1.5 & 1.4) didn’t work. I now get the podcast title and progress.
Not displaying podcast artwork, but I have never seen this in my car with any podcast app… although I do get album art with VLC.