Found the report you are talking about, so he tried to buy weapons from a Ukrainian arms dealer, and he claimed to have fought in Ukraine. Trouble with your story is that it falls apart when you do even the most basic of digging:
A former volunteer for Ukraine's International Legion, Evelyn Aschenbrenner, branded Routh as "delusional" and a "liar" over his claims that he recruited for the Ukrainian organization, saying Routh was "not, and never has been, associated with the International Legion or the Ukrainian Armed Forces at all". Aschenbrenner said of Routh "He was combative. He was argumentative. He refused repeatedly to understand basic army policy", further adding "There was delusions of grandeur and [he was] very disconnected from reality". The International Legion for the Defense of Ukraine said in a statement that Routh had "never been part of, associated with, or linked" to it "in any capacity."
I mean, imagine thinking the Ukrainian government used that dude to try to assassinate Trump. As for your claim about Ukraine interfering with the US election, there is zero credible evidence for that. Al there is, is online ramblings from conservative lunatics.