Is it a non-competition restriction for a new company to invest in a competitor company of the old unit?

Not exactly. The new company's investment in the competitor company of the old company does not involve the competitive relationship between the original employer and employees, but belongs to the investment behavior between enterprises and does not constitute a non-competition restriction. Non-competition refers to the act of restricting workers from engaging in business activities that compete with the original employer in the same area within the prescribed time limit after the termination of labor relations.