That is the only solution.
However, in may 2017 Theresa had an unnecessary election in which she lost the Tory majority and had to get into a coalition with the northern Irish party the DUP which opposes what you described.
Since then, everything is stuck. Thanks to the DUP
Since Boris wants the government dissolved, adopting the plan that I have described ought to do nicely as a way to get the DUP to help trigger an election.