Much longer than you think.
The median time (which means an average amount of time where the extreme outliers are removed from the equation) to reach remission is 18-22 months.
That is one and a half years for almost everyone who enters, and sticks with, the recovery process. For a tiny minority it will be a few months, and for some it may take up to 79 months.
You do not keep gaining weight the entire time. The weight stabilizes whenever the body is good and ready to have that happen, but there is a lot of physical repair that has to be managed beyond that point.
The minimum guideline intake is what non-ED people eat every day on average to maintain their weight and health. It is therefore what you will eat comfortably every day throughout the entire 18 months and beyond into remission, with the exception of periods of extreme hunger which are expected in recovery to support repair.
Many assume that their experience with restriction was so short or not severe that it will mean that they will be in full remission in a matter of just a few months once they are committed to eating to the guidelines every day and resting.
However, no matter your history with your eating disorder, you have a statitsically far greater chance of needing 18 months, and not less, to reach a solid remission.
Try to frame the experience as being respectful of the fact that your body has to repair a lot of damage and that it deserves the time it needs to ensure you have a long and healthy life in remission.