Is the usual translation of “ηὐχόμην” as “I could wish” justified in Romans 9:3?

As an imperfect it has a sense of continuation "I wished and continued to wish". Middle is usually translated as active, so Paul is doing the wishing. Indicative indicates it is an actual fact.

"I, Paul, really did wish and continued to wish..."

So is a conditional simple "I could wish" an equivalent? I could wish for a better one. It kind of loses the indicative sense of being a fact and makes it sound conditional.

This is the essence of true intercession as practiced by Adam (willing to give up his life to be with his wife), Moses (willing to lose his place so that Israel was not destroyed), David (willing for God to take his life rather than continue to punish Israel), and Jesus who was made to be sin so that we could become the righteousness of God.

We are lightweight intercessors when we tack on a few more lines to our prayer to make sure God knows we're serious.

   Greater love hath no man than this, that a man lay down his life for his friends. —John 15:13