No, going third-party won't get it done. A putsch within the GOP similar to F. Clifton White and Barry Goldwater's 1964 successful insurrection is your better model in terms of outcomes down the road.
We have sweat, money, and vote equity in the GOP. It isn't the property of the Atlantic Seaboard Yacht Club types or the Harvard Porcellian Club or Yale Bonesmen, nor of the Business Roundtable.
Oh I’m not proposing a third party, just pointing this is how party’s die, like the Whigs.