Try this on for size...
1. grabbed by the wrist from front. step up and to the outside of the attacker (keeping your elbow in tight). If they hang on their wrist is bent outwards, your free hand grips onto their wrist and you can use leverage instead of strength to pull free of their grip, from here an arcing backfist is easier than the upright one.
This format for Saifa can be seen in goju version. And this all takes <1 minute to demonstrate, plus there are some refinements which aren't strictly necessary but are a bonus if you get them
2. being struck at from the front. sidestep into sumo and parry with both hands, rear hand grips the arm of the striker and drop a knee/shin into the back of their calf, taking them to the ground.
3. being grabbed by the wrist (another). free hand is used to control their grip, step underneath the attacker's arm in your sumo, your elbow comes under their arm, rotate their arm outward and raise up to lock their elbow joint.
4. being grabbed by the wrist (another another). free hand is used to control their grip, step alongside the attacker's arm, your elbow comes over their arm, rotate their arm inward and use your sumo to drop weight onto and lock their elbow joint.
That oughta be enough, for starters
Mick