Yes, Trump can probably still expect a second acquittal in 2021. But Trump has three main post-presidential goals, and the forthcoming trial will do severe and possibly lethal damage to all three.
Trump’s maximal post-presidential goal is to position himself for a comeback run in 2024.
Failing that, Trump would like to demonstrate that—president or not—he remains the dominant force within the Republican Party, a leader surpassing all others.
Falling even that, Trump would at a minimum like to prove that he remains a potent-enough figure to frighten away federal and state prosecutors from investigating his businesses for tax or bank fraud.
The second impeachment in the House has already complicated these goals. The second trial in the Senate will complicate these goals further.