deficit diets don't actually work the way you think. if you lost 1 pound a week forever eating in a deficit then after 200 weeks you would weigh 0.. doesn't work like that
How long can you go in a defecit depends on the amount of defecit you are running, what your daily expenditure is, and how often you are refeeding etc.
8 weeks in a moderate defecit is fine. I dieted hard in a defecit fir a contest for 16 weeks, bit that was prep....a whole other level
It's depend person to person and lots of factor when I was 28year I did my 1st transformation and it's was just awsome only 90 days I achieved single digits body fat so lots of factor work here