I've recently learned how to do this. I don't know why I put off learning how.
It cooks really fast, but ALSO ends up better. My son is fussy about meat - really can't stand anything slightly dry or tough. He demolishes it when I prepare it this way, and often refuses to touch it otherwise.
Use a meat thermometer, rather than time. Aim for 65 degrees C at the thickest point, and let it rest for 15 minutes before carving. Tonight a whole chicken was being dished up 60 minutes after going in the oven.
Spatchcock is a great method when grilling or bbq’ing chicken, it cooks so much more evenly.
If you can be bothered to completely debone your chicken for a roast, the meat stays really moist and the stuffing can stretch the chicken to feed up to eight people if you have lots of roasted vegetables to serve with it - cauliflower cheese, a potato and leek gratin, sweet potatoes, beetroot, carrots, broccoli etc all get cut up and tossed in olive oil and seasoned.
The late Jacques Pepin’s video demonstration of how to debone a chicken is the easiest one to follow.