You obviously do NOT understand leverage. Never allowing for a third party removes ALL of your leverage, as you tell your opponent there's no competitive threat. You give them ZERO incentive to move toward your position.
I also understand what will happen if democrats take over all levels of government while the GOP is trying to “leverage out” the RINOs.
You mean like what ALREADY happened a few days ago?
The democrats did not take over all levels of government on January 20. It has been like this before when obama had the house and senate for two years, 2009-2010. I expect the GOP will take the house again in 2022.
If a third party shows up and splits the GOP vote, the GOP will never get back any part of the federal government and will end up losing many state and local governments as well.
If we had a parliamentary government, I would be all for a new party, but we do not.