Free public CORS proxies are the weak link. A relay you own eliminates all limits. On Cloudflare (free tier): create a Worker, paste the code below, deploy, then put
https://YOURNAME.workers.dev/?url= into MY PROXY.
export default { async fetch(req){
const u=new URL(req.url).searchParams.get("url");
if(!u) return new Response("pass ?url=", {status:400});
const r=await fetch(u,{headers:{"user-agent":req.headers.get("user-agent")||"Mozilla/5.0"}});
const h=new Headers(r.headers);
h.set("access-control-allow-origin","*");
h.delete("content-security-policy");
return new Response(r.body,{status:r.status,headers:h});
}}