I will assume that you had good relief from your first surgery 4 years ago and had no residuals such as triceps weakness. New foraminal stenosis at C5-6 will compress the C6 nerve which goes to the biceps muscle and the wrist extensors (pulling the hand back). C6 can occasionally affect some types of grip but grip strength is generally considered the C8 nerve (C7-T1 level).
Decompression from behind is acceptable for foraminal stenosis but if the compression is from uncovertebral hypertrophy (from the front-not the back of the spine), the surgery is not as effective.
You can try epidural injections or even oral steroids but you might need surgery with the weakness you exhibit (however, make sure you confirm the weakness is generated by a C6 nerve problem which is still to be determined).
https://neckandback.com/conditions/radiculopathy-pinched-nerve-in-neck/
https://neckandback.com/conditions/symptoms-of-cervical-nerve-injuries/
Dr. Corenman