Probably the best outcome for Boris. Rishi loses the next election proving that the Tories need someone special to lead, Up steps Boris. Always easier to govern when at a low as it was when he took over the first time.
Boris is the only one with a mandate to be a PM. He was elected for 5 years, he should serve the 5 years. Anything else is undemocratic and I would support an early general election if it wasn't him.