It wasn't attempted bribery - it was bribery

Republicans claim that Trump's aim of using governmental funding to obtain a fraudulent investigation by a foreign power as a way to skew the 2020 election doesn't matter because the withholding "didn't happen" and the money was released.

It did happen.

The money was withheld for two months, possibly longer. Ambassador Taylor learned about it in mid-July (it happened sometime earlier than that), the Ukrainians knew about the hold in mid-August, and it was released on September 11 after public pressure caused by the whistleblower's complaint. For a country at war with a more powerful neighbor occupying part of its land, this withholding period isn't nothing.

Whether Ukraine gave in to the bribe offer in some form is immaterial, but it did. In addition to the well-known plan to announce an investigation during a CNN interview, Ukraine announced it is "auditing" the past investigations of Burisima. Trump didn't exactly get the fraudulent investigation he actually wanted, and it wasn't announced on CNN, but he did get the investigation he claimed to want.

Again, the difference between attempted bribery and completed bribery is immaterial as to whether Trump should be removed from office, but regardless, it was bribery that withheld military aid from a friendly nation under threat from an adversarial power.

Finally, each time Republicans talk about how important it was that Trump ultimately released military aid that Obama opposed, they're complimenting the whistleblower, because it's the whistleblower's action that got the aid released. (And of course, Obama did provide non-lethal military aid, wasn't violating Congressional direction, and had reasonable policy arguments for his position, but all that is ignored in the Republican talking point.)