No matter what his true motives were, Trump isn't technically guilty of any impeachable offense.

. . . and as far as "Obstruction of Congress" goes , every President has done that since Congress was created !

The left is woefully ignorant of many things, including this treaty:

Treaty with Ukraine on Mutual Legal Assistance in Criminal Matters, ratified by the U.S. Senate on Oct. 18, 2000.

https://www.congress.gov/treaty-document/106th-congress/16/document-text?overview=closed
https://www.congress.gov/106/cdoc/tdoc16/CDOC-106tdoc16.pdf

Zelensky was well aware that the U.S. military aid was held up as of the time of the July 25 phone call. Trump didn’t mention it explicitly because he didn’t have to.

Here’s a pretty full timeline. June 2019 onward is particularly relevant for this.

https://talkingpointsmemo.com/news/whistleblower-ukraine-biden-trump-schiff

Sorry, no Zelensky didn't know the funds were held up and he stated that he was unaware that he was being bribed. This he stated himself. Check your sources.