YYC-FRA is rumoured to come back eventually. It's been mentioned multiple times on here (I believe it to be true) that it was handed over to Lufthansa/Discover temporarily while AC focuses on YYZ/YUL/YVR. I've heard that it will come back when enough 787-10 come online.
There probably is a reason why they have not closed the YYC FA base. They could have closed it during the negotiations in 2025, they didn't.