Prince Harry has chosen to opt out of the royal Family, go to the USA, settle there as a private citizen and bring up his children there
If he would just settle down quietly, as a private citizen, people would soon forget about him and his irrelevance to the royal family and he would be highly unlikely to attract adverse attention.
The USA is peppered with the scions of other European royal families, who have chosen to opt out of being royalty, settle in the USA, with their, usually American spouses and just drifted into normal life.
The reason this isn't happening to Prince Harry is because he will not let it. Ever since he left he and his wife have been making films, taking part in tv programmes and writing books all about themselves. Where other royals in privacy in the US have bought 4 bed detached houses in pleasant neighbourhoods, got jobs and lived a normal life, the Duke and Duchess of Sussex have chosen an oppulent lifestyle among the very rich, which requires a lot of money, more than they have, to support it. They can only get this money, with their limited personal attainments by flogging themselves, again and again and again.
If he is going to constantly put himself on the public stage, so that he does draw adverse attention and require constant security, why on earth should we pay for it?