I think you underestimate Trump and Giuliani. It's more likely that a Republican voting to convict can be certain that their crimes will not only be uncovered, but prosecuted.
Rudy is excellent at and experienced at prosecuting organized crime. Most people know about and understand a criminal being granted immunity and put into the witness protection program, but there are other deals as well like someone not even indicted but shown evidence against them that is then put aside for the time being.
There are a lot of deals that can be made without the source being identified in public or even putting discussions with them put into the record. For example, "give us what we want and in return you won't be prosecuted or identified as long as you cease and desist". There are a whole lot of deals made that most people don't know are made and often don't know that such deals can be made.
The prosecution gets what they need, the smaller fish swims free but has been "tagged" and no one is any the wiser.
Rudy's been pretty much M-I-A since his two cohorts were arrested and accused of campaign donation violations.
The night before, he was on fire on Hannity, talking about how Biden's been getting away with his crap for 30+ years, and was the first one to mention that there was something big about the Bidens in Romania.
Next day was the arrest and I haven't seen Rudy on any shows since then.
We're gonna find out one way or the other but this thing has been drawn out for so long, I wouldnt be surprised if nothing happens before the election.