Oops, I see I accidentally missed out some important underlined words from my post. "who appoints
the chairman/CEO of Openreach".
For example years ago now, but a while after BT bought Plusnet, I checked some corporate facts and found the "wholly-owned independent" Plusnet CEO remained on BT payroll, and PN reimbursed his salary. Not quite as independent as claimed then! ROFL. I did post about it in the PN forum at the time, as they were my ISP.
Re the part you now highlight, yes. I read that when you posted the link but the full significance didn't sink in

. It opens a number of options.
One possibly being substantial funding aid for some of the smaller AltNets in return for being able to use their network rather than have to build out to the same area. Whether that would be for just direct BT end user consumer and business supply, or BT Wholesale and its CP customers, or Openreach in general, is another question.
Most likely the first of those, otherwise the small provider would be wiped out. Effectively bought out.
Numerous non-landline options are of course possible, perhaps via agreements by EE and providers like Starlink.