You don't even really need the testing. Everybody will either benefit or at least not be left worse off from eating high fiber and low saturated fat. Getting a sufficient electrolyte mix is not a real concern for anyone who isn't regularly exerting themselves in high heat and is then only a concern during the exertion. Exercising and sleeping well will give exactly the same benefits regardless of whether you also track VO2 max and sleep quality score.

Early detection of cancer and CVD are great but fairly standard anyway if you just follow recommendations that already exist.