I hadn't heard of the set point theory before, but this is what happens to me.
I actually signed up to WW again last week because they are offering a free 1 month trial and I wanted to access my.old records. I was a member from 2015 to 2021 when I had my baby, and I've managed to download my entire weight history from those 6 years. I've also kept records from 2022 until now, so I've input the lot into excel and compared every date of each year (what a nerd 🤓) and it's been extremely eye opening. In short, I KNOW I can maintain my weight, I just can't lose it once I've gained it. The graph very clearly shows the three attempts I've made, but I spend the entire time in the same 9lb "window" of weight.
I'm now the lightest I've been since the end of 2017 (which is when it all went very wrong).
22lbs down, 18lbs to go.