You are correct in that Trump did tear up the Republican Party, just not in the way that you think.
The new Republican Party is built on Native Americans and Pacific Islanders, both of whom, though small groups, voted majorityly for Trump. It is also the beneficiary of at least 1/3 of all Latinos, midway between 1/4 and 1/3 of LGBTetc., the working class, 20% of Black men, and half of college educated professionals. This is the most multiracial and ethnic coalition for the Republicans since Nixon began the Southern Strategy.
It held and it won down ballot. The Republican Party did not lose, Trump did. The Gains in the House of Representatives will make governing there practically impossible on a progressive Democrat basis.
Picking up 192 and counting state house seats and 40 state senate seats comes close to undoing the loses of 2018.
The Republican Party in its new constituted state is alive and well, can you say the same for the Democrats? Btw am neither a Democrat or Republican, just an observer, a viewer of the scene.