If my wrists feel weak I like to train the wrist extensors and flexors gradually.
I take a thin strong rope, tying one end securely around a lightweight dumbbell or barbell plate and tying the other end to a short (preferably wooden) dowel or cylinder, carefully securing it to the middle so it doesn’t slide. Drilling a hole through the dowel and pulling the rope through works the best.
Sit down, take the dowel in both your hands in front of you and roll the dowel slowly forward, gently curling the wrists so the rope wraps around the dowel and the weight raises up. Lower it slowly and repeat in the opposite direction.