Hernia Risk with Cervical Spine Flex?

Are neck exercises safe? As in, are they like thoracic spine movements (safe) or like lumbar spine movements (unsafe)? I want to start training my neck using a harness, and am wondering if it’s ok. (this considering all conditions of gradual progression, rest, good form etc. are satisfied)
Usually, if my neck hurts or feels stiff, a few minutes of neck extensions make it feel great for a long time.

I’d greatly appreciate feedback.

Thanks, Vlad

How’s your posture first and foremost?

I’m not a fan of neck exercises but it depends on what you are training for?

Powerlifting? Body building? OL?

A big strong neck. Technically, I train to be strong and big (and healthy).
Vlad