Openreach needs to be split from BT as the latter is using the former to subsidise it's TV and sport plans to the detriment of everyone else
We don't know that, even though most of us suspect that. That's why strong regulation of Openreach could be a suitable answer. If BT shareholders want to own a content aggregator and a utility, that's fine by me. But the two businesses need to operate as separate legal entities and at arms length. Any "cheap debt" advantage of a regulated Openreach needs to be firewalled from BT's other businesses. And the regulatory risk of a potentially capricious, interventionist and incompetent regulator (a big shout out to OFEGM in this respect) would be kept away from the non-regulated operations.
Given that BT's only position is that the status quo is the best and only answer tells us only one thing: That the answer is almost anything but.