You posture is completely broken throughout the length of the body and yor legs are splaying apart really widely, this is incorrct swimming posture, you have no taughtness or connection.
You not progress until you achive POSTURE LINE & BALANCE
Spent time floating face down in streamline position everytime you go to the pool, even take 3 strokes and go into a pencil float to remind of correct posture
Get level on surface in streamline and start to pull yourself along from there never losing that level taught streamline position.
(when they say implode that means what i said earlier suck your ribcage up and in to connect hips to shoulders through the core