You can just read the quoran and using basic reading comprehension tell if they are following it or not.
Except Christians are not under the same covenant as the original Israelites. We are under the new covenant that writes the laws on our hearts. So we desire not to do wrong and to try to do right.
The prohibition against wearing a garment of "linen and woollen" (mixed fabrics) likely served as a reminder of spiritual purity. It may have warned against syncretism—blending Israelite worship with the idolatrous practices of neighboring cultures, who sometimes used mixed materials in rituals tied to fertility cults or other spiritual practices.
While the primary purpose is theological, some practical reasons may apply. For example, crossbreeding different kinds of cattle (e.g., producing mules) could complicate farming or result in sterile offspring. Mingled seeds could lead to inconsistent crop yields due to differing growth needs. Linen and wool have different properties (e.g., dyeing, washing, or wear), so mixing them might produce less durable garments, though this is secondary to the symbolic intent.
Essentially we no longer have to worry about those kinds of things.