They did as thorough a job as they could given the three or four important witnesses whom Trump ordered not to testify, despite subpoenas. Now we'd like to hear from these people so the evidence is more complete. But the last thing the GOP wants is complete evidence.
But they (the Dems) refused to argue their subpoenas in court. They even went so far as to pull John Bolton's subpoena after he, himself, went to court to see if he could testify.
That's right, John Bolton said he wanted to testify and went to court to see if he could. And then, the Dems pulled his subpoena. Not the best optics for their case.
So, no, they did not do a thorough job. If they were really concerned about the country, they would have done their job and taken the subpoenas to court (like with Nixon) but did not.
Since they lacked the courage of their convictions, I see no reason why the Senate should do their job for them, unless of course they are okay with Hunter Biden taking the stand.