As someone who generally leans towards the conservative side of government spending, I actually quite like this Labour policy. Broadband has become as important as other utilities and centralising it should improve connections in rural areas, that just don't make financial sense for private companies.
However, they've not pitched it right for me. This was the perfect opportunity to scrap HS2 and make the argument that improved home internet would make remote working more viable for more people, thus adding more to the economy and limiting the need for additional high speed transport into London.
As it is, I suspect it's just more Labour spending to be paid for by increasing taxes and borrowing.