Late Thursday Congressional Democrats released a trove of text messages obtained from the phone of former Ukraine special envoy Kurt Volker. The text message paint a picture of heavy, sustained involvement of US diplomats engaged in a clear effort to establish a quid pro quo in which the Ukrainian deliverable is investigations of Joe Biden and Crowdstrike, while the US deliverable is at times confirmation of an official White House visit for Zelensky, and at other times is both the visit and security assistance.
Following are screen shots of the texts as released by Congressional dems. (I have added highlighting of key phrases.)