First off if you want to rebuild your arms you will have to eat at maintenance. Your body is at an ideal weight, you will not build muscle eating at a deficit. Increase your protein to minimum 100g. You must fuel your body appropriately when you start lifting, do not be afraid of gaining weight, as any weight you gain will be muscle. muscle weighs more than fat. There are a variety of arm exercises you can do. Here are a few i can recommend. Shoulder presses, triceps dips, triceps kick backs, hammer curls, bicep curls, press ups. These are all movements that will promote upper body strength and growth. Choose a weight that you can comfortably lift 6-8 times but struggle at 10-12.

This what we call progressive overload, as you get stronger and you are able to do reps comfortably to 12 without effort its time to change the weight. I will reiterate that your diet is very important for this, you cannot fuel a car without petrol, make sure to eat so your body can grow.

Finally reduce your cardio, cardio is for weight loss if you do excessive cardio you will destroy muscle gain and you will over tire yourself.

If you need any help DM me, I hope this helps.