Numbness can be a lot different things, hard to know without some diagnosis.

"Long-term numbness or a tingling feeling in the legs and feet may be due to conditions such as multiple sclerosis (MS), diabetes, peripheral artery disease, or fibromyalgia. The sensation may be felt in the whole leg, below the knee, or in different areas of the foot."
-- Numbness in legs and feet: Causes, symptoms, and treatment:
https://www.medicalnewstoday.com/articles/321560