You will first probably need Congress to legislate away the long standing prohibitions against offering (easily) user-modifiable RF devices on the market.

Self ownership and full 'right to repair' has carve-outs in the FCC's regulations in the name of limiting unintentional broadcasting/radiation. Maybe a challenge to those would survive in the post-Chevron environment. I wouldn't expect any Congress in the last 25 years to pass a law which would go against the incumbent telecom lobbyist interests though, and I'd expect such a hole if it did hit case law, to get 'patched' fairly quickly.

About the only way to really solve that would be to embarrass vendors enough to open their moats.