If you have a DUI (and answer honestly) don’t waste money or time on an ETA as it will be denied. And no, I am not suggesting you shouldn’t answer honestly, just saying that an ETA application is not going to be approved.
I have one on my record. ETA denied. Filed a regular tourist Visa Application - sent my FBI record with the application (already had it as it’s a work requirement). It came back Approved in a little over a week.
i did not want to wait for them to ask for the FBI paperwork (or God knows what else they might have asked for if I hadn’t sent it), I just attached it to the application and it sailed through.