It is illegal to use taxpayer money to bribe a foreign government to try helping you in an election. Furthermore, it is embarrassing an act of desperation. This act alone is impeachable, and there are many other acts which only fuel the fire. Republicans have no excuse but to work with Democrats to impeach that guy for using taxpayer money to his own personal benefit.
Ukraine didn't even know the funds were on hold when the call was made. Even if you believe the quid pro quo was implied, how does that work if there was no evident penalty or gain? Lets assume for a moment Biden is guilty of the crimes he is accused of. Exactly how should Trump have asked for a legitimate investigation? Impeached for asking corruption be investigated? What "other acts?" Exactly how is he using taxpayer money and gaining personally and Biden not?