There is no such thing as the general best treatment, but rather best principle, as the treatments need to be prescribed individually subject to the physio objective assessment results.
The principle may not be of much use to you, as there is a gap on how to form and implement suitable treatments to meet the principles. But here are the principles:
- nerve compression is a result, not so much the cause for neck stiff; it's rather the cause for referred pain (but you haven't mentioned, so I assume the referred pain is either non exist or not of your main concern)
- neck / joint ROMs need to be kept optimal
- environmental factors needs to be investigated, i.e. pillow, chair
- posture need to be addressed, if found contributing to the problem
neck stiffness is mainly caused by malalignment, disc, joint or muscle problem, with some % of sufferers' cases that are due to apprehension.
joint can be categorized into deformed or non deformed, and they have different type of presentations under each sub-category, hence treatment approach is different subject to assessment finding
muscle can be tight, jerky contracting, thickened, imbalance..etc, all of these can also contribute to neck stiffness, and again, treatment approach is different across the board.
loss of disc height can often contribute to some degree of stiffness, but with differnt kind of disc pathologies, e.g. bulge, prolapse, loss of height, spondylolithesis ..etc, it's another huge topic of discussion.
On the other hand, further Q needed to be asked by your treating physio on what you described as discomfort, as discomfort can be pain, stiff, combination of both, or in other form. Once this is clarified, specific assessments need to be conducted to investigate the cause of this discomfort, before formulating treatment strategies. Just because there is nerve compression found, it doesn't mean every discomfort you've experienced in neck is all coming from this compression.
An experienced physio would know what he / she is doing, so able to provide you more immediate result and carry-over effect, hence gradual recovery; less experienced clinician may have no idea what to look for or may require more sessions of trials and errors before getting the root cause of your neck stiffness right.
Maybe speak to your local experienced physio will be a good start.