No party's platform is based on ending or destroying social security, especially not the GOP who gets a broad base of support from retirees. That being said, I've never had much faith in it being around for myself, though I'm 30 years from eligibility). It's possible that productivity boosts from automation and AI could overtime make SS actually sustainable in spite of overwhelming boomer population to support.

The federal tax revenue as percentage of GDP is remarkably stable regardless of widely varying income tax rates over the decades (ranging 15-20% since the 1940s): https://fred.stlouisfed.org/graph/?g=ockN. This holds up no matter which regime (D or R) is dominant, because the economy reorganizes itself around incentives or disincentives created by various tax policies.