Honestly, I don’t think the Torfaen result proves anything other than that Reform mobilised supporters, as there was a 24% turnout, and less than 1000 votes were cast in total.
There’s no doubt that the Tories are in the doldrums at the moment, but they still have some decent MPs, and when Badenoch has gone I think their fortunes will revive. A lot is going to be learned from what’s happening in USA, and I think the Tories will move back nearer the centre, because that’s where the votes of the majority are, and there will be more there when Trump’s economic policies fail to deliver - bearing in mind his term will be up before our next general election.