Urgh. Complete mess. In answer to the OP, no I don't think it is the end of the Conservative party. What is happening though is the purging of non-eurosceptics and moderates, to be replaced by sycophants of Boris and Brexiteers. The result will be a more extreme anti-europe party, not its eradication.
On the streets, in the pubs, in the cafes, purely anecdotally my feeling is that the people want Brexit done. 'Just get out' is the mantra I hear. The nuances of a deal, Northern Ireland etc. doesn't mean much to a good proportion of the electorate. The brinkmenship of no deal will win over the people who would vote UKIP/Brexit Party and I think they stand a good chance of winning an election. There is a widespread distrust of Corbyn among a wide range of people. His core support love him, but outside of that, in my experience he isn't much liked. My feeling is that the 2017 was a bit of a fluke. Idealistic student voters we motivated and Teresa May had some own goals with the so called 'dementure tax' and ran a very uninspiring campaign. I don't see these circumstances being repeated.
For what its worth, I am disappointed by the descent. I am struggling to decide on who to vote for. I could never vote for a labour party hijacked by student politics of envy, with an agenda to punish the successful and treat villains as friends and friends as villains on the international stage.
However, the climate in the conservative party, and constructive dismissal of moderates that are doing their jobs, i.e. standing up for what they believe in, and what they believe to be in the best interest of their constituents, I'm not sure I want to vote blue.
Lib dems will do well, but won't win because so many want Brexit. And a good LD showing risks letting JC in through the back door as leader of an opposition alliance.
Least worst option? Possibly Conservatives and pray to god they can get their act together and return to their centre-right roots. A sensible modern labour party would get my vote if they existed.