Season 9 storyline?
I recently discovered, binged, and fell in love the The Royal. Like a lot of people the cliffhanger at the end of season 8 had me screaming at the TV.
That said, I think the show was hinting at a potential story thread for the season 9 that they didn't know was not going to happen. It would be Sister Brigid leaving the order.
Throughout the series they showed that she had longings for at least a child. Every time she picked up a baby there was a reluctance to let it go. Then with her niece Aisling and the adoption. Her stiff and stern Mother Superior revealing, at least while under the after effects of anesthesia all the regrets of becoming a nun. The same ones that she had. Then in the last finding out that poor woman was raped by a priest and forced into a mental institution because she was preggers with his child and just the attitudes of the nuns in charge of the place.
I bet in season 9 there would've been a blow up between her and her Mother Superior over the report the other order submitted. She's probably ordered to cease being a nurse and be cloistered in the convent. That she WILL be a proper nun. Given that, I bet she just leaves without permission which back in those days could mean excommunication.
I have no doubt that Linda Armstrong could've done a stellar job in such a storyline and even more so as a former nun learning to be in the outside world.