I may be wrong but is it possible to control it with the Bang and Olufsen app (which replaced the Beoremote app)? The TV would have to be connected to be connected to the same network as the phone, so this will only work if the TV is able to connect based on its previous settings. It could be worth connecting the TV directly to your router with a network cable, and then see if the B&O app can find and control it.
It’s just a thought – I don’t have such a modern B&O TV 😀