You may need multiple PT sessions to resolve the problem.
If this is something that has been an issue it is going to take some time to resolve.
Same as breaking a bad habit with a movement pattern. It is hard and takes time to change.
In this type of situation you’ll need to mobilize various times throughout the day. For example morning, lunch time, dinner time. Repeating the stimulus for the changed movement pattern, technique change etc. will help to improve the technique and establish a new movement pattern & neuro pathway.
Have you look up and down stream of the ankle?
This issue may not originate at the ankle. This is where you see it, but it may not be the root of the cause.
Until you identify where the issue originates and address that the problem will continue because you are addressing a symptom of the issue not the causexof the issue.
Have you addressed the cause of your foot collaping?