That claim is not in evidence. Trump has a track record of still being rankled as to the Ukrainian 2016 election influence, and also has a treaty and legal obligation to promote Ukraine's investigation into corruption by Americans dealing with an in the Ukraine.
Are you seriously supporting the idea that Trump is concerned about the 2020 election and Biden as a election opponent? Ask yourself, why would an incumbent, and all the advantages that brings, along with a strong economy and all the advantages that brings, as well as a strong record of promises made and promises kept, why would such an incumbent be concerned about a weaker campaign opponent? When was the last time an incumbent lost with these set of conditions?
No, the focus has been on the corruption and the election 2016 influence, and not likely anything to do with the up coming 2020 election, clearly. What I will grant you is that it hasn't been conducted in the best and wisest way possible.
In examining the truth, being important as you've stated, you have also ask yourself the Democrat's motivation in bringing impeachment, as they've clearly stated their intention to impeach Trump only moments after the election was called, and the motivation as to why has been clearly explained:
The Democrats and their supporters continue to claim 'the evidence is overwhelming', but if the evidence was overwhelming, why are the Democrats demanding the introduction of even more 'evidence'?
The segregation of duties is quite clear: The House investigates and drafts the articles of impeachment, and the Senate hears those articles and that evidence.
If a prosecutor arrives in court to try a case and his first statement is that 'we need to find more witnesses, more evidence', the judge would promptly reply with 'why did you bring the case in the first place?' and rightly so.
Such is the Democrat's idea of overwhelming evidence? Don't make me laugh.
Demonstrated that the Democrat's case is weak, ill prepared, and of questionable foundation.
Demonstrated the Democrat's motivation is strictly partisan politics, and is clearly not in the benefit of the United States.
Demonstrated that the Democrat's motivation to impeachment started before Trump even took office.
My advice to you is to stop watching CNN and MSNBC, they are manipulating you and you are falling for it, allowing yourself to be manipualted by them.