I still see a chance of conviction, even if it's not necessarily likely.
The GOP likely realizes that giving in to Trump's pressure and letting him run for office in 2024 also means the party is chained to him for the next four years, like it or not. If he stokes more violence or goes to prison, they have to pay for it. And remember, Trump just cost them the Presidency and the Senate in one go after losing the House in 2018 — does the party really want him motivating Democrat supporters to deny Republicans in 2022 and 2024?
There is the risk that Trump will take many voters with him if there's a Senate conviction, but there's also a chance he'll split with the GOP anyway. A Senate conviction would prevent that split (at least with Trump at the helm). And let's face it, many Trump supporters would vote for the Republicans anyway, despite protests to the contrary.