Oh don’t worry, it’s not petty - debating translation is good because it’s hard to get right.
You right, you line would work in my example. I only gave the example, however, so that the line had context.
Using ‘play it by ear’ would only work if you were the doctor - it literally means you made it up as you went.
(c.f.: “I’m not sure what to do, I’ll play it by ear”)
This is why I wouldn’t translate one as the other - you created an implication that just wasn’t there in the original copy from Team Radiant.
“It’s always a bit touch and go in the early days” => Life is hard for a new colony (no implication of ‘making it up’ as you go)
Hope you don’t find that pedantic , I quite like debating idiom.
Edit: for completeness: