Unable to delete podcasts and iPhone storage too full

I am unable to delete podcasts from iphone XR.

Its automatically set to "delete after playing" - but they do not delete (only noticed it in the last few weeks - might have been related to having to wipe the iphone and reinstall all apps / etc about a month ago).

When I manually delete episodes - they come back within seconds.

When I unsubscribe from the podcast - the downloaded episodes still remain - even after manually trying to delete.

When I deleted the podcast app - the episodes are still taking up storage room in my phone and cannot remove.

I only use the podcast app (i.e. not through iTunes or other device).

Cannot upgrade to ios16.2 as dont have enough free storage (due to podcasts taking up ~2/3 of storage even after deleting the app).

Am currently on ios 16.1.2.

All help greatly appreciated!