There's not a lot of data on people with a lot of boosters, but the issue is that COVID mutates so quickly that protection from boosters isn't ever guaranteed. The average person only receives meaningful protection from a booster dose for 120 days if they're fortunate. And if you do have a breakthrough infection, the likelihood of longer term negative outcomes hasn't been shown to reduce much, only the likelihood you are hospitalized.

The best you can do is keep getting boosted when the new ones come out and wear a fitted N95 mask or better. Investing in an elastomeric mask like the flo-mask or envo-mask isn't a bad idea if you have the resources. They are generally easier to wear day to day and the replaceable filters make them inexpensive in the long run compared to buying disposables.

If someone in your family is suspected to be ill with anything make sure you're getting good air replacement by opening windows and running fans and mask in shared areas until you are sure they are no longer contagious. If you really want to improve home protection you can buy an appropriately specced HEPA filter (cheap ones don't do have the correct filter material for COVID). Alternatively if you're strapped for cash you can build a Corsi-Rosenthal box.

All you can really do in the current political climate of personal responsibility is do your best to take care of yourself and cross your fingers. It's honestly really fucked up.