Hello OP. You really have my sympathies. I went through this recently but with my 2 years old who is no longer in a cot so controlled crying wasn't even an option as he never cried, he just got out of bed...rapid return at that time in the morning is just not feasible unless you want to sent yourself to the mad house and the rest of the house mad with sleep deprivation.
We tried wake to sleep and it did work. But ultimately he just broke his own habit after about 5 weeks.
He's now waking near to 7pm most days, apart from yesterday and today of course, which was 6am
Really good luck. In your shoes I would CC I think, for a week and see. I did that with DD when she was waking at 5am (long time ago now) and she would cry for a bit, then just sort of protest a bit, but was often back to sleep within 20 mins to half and hour of waking.
You know the drill with CC. In, no eye contact, shush shuh, pat/stroke and out. First at short intervals, then at longer ones, but most people agree not more than 10/15 mins without going in.
Dr Tanya Byron has helpful nice things to say about CC in the right way