The Senate doesn't want him to testify, they don't want any one to testify. Hopefully those Dems in the House subpoena him... That one should be interesting haha
The last I read suggested the likely Senate rules will be similar to what was used during the Clinton impeachment.
The major difference being, of course, the GOP majority in the Senate wants to shorten any "trial" as much as possible (this was not true for Clinton).
I expect the House masters will present their case, the GOP might have some argle-bargle defense presentations (money was finally released, what about Hunter Biden, etc.), and the Senate will vote along party lines. No witness testimony, no further evidence presented.
Much like all the idiots who claimed the white cops who weren't indicted when they shot unarmed black people (Michael Brown, Tamir Rice, etc.) received a "fair trial", the GOP and their supporters will claim Trump was 'exonerated', and the Kabuki theater of our current politics will continue.
Everyone doesn't loathe Trump .. seems the entire Republican party thinks whatever he does is fine. Democrats don't even "loathe" him .. they just think he's doing a horrible job. I hope Bolton (and others) get to testify .. but I doubt that's going to happen.