Right now the numbers below are baked in as a dated snapshot so the page works offline. To make the dropdown pull live quotes, point each ticker at a data API and replace the values in the DATA object. Browser CORS and API keys mean you’ll want a small proxy — which you already have available on Cloudflare Pages Functions.

1. Pick a provider with a free tier (e.g. Finnhub, Twelve Data, Financial Modeling Prep, Alpha Vantage). Quotes are easy; analyst targets and options open interest need a provider that exposes them (FMP / Tradier for OI).
2. Add a Pages Function at /functions/quote.js that holds the key server-side and forwards the request — keeps your key out of the browser and sidesteps CORS.
3. Fetch on dropdown change and merge into the ticker’s data object, then re-render.

// /functions/quote.js  (Cloudflare Pages Function)
export async function onRequest({ request, env }) {
  const t = new URL(request.url).searchParams.get("t");
  const r = await fetch(
    `https://finnhub.io/api/v1/quote?symbol=${t}&token=${env.FINNHUB_KEY}`
  );
  return new Response(await r.text(), {
    headers: { "content-type": "application/json" }
  });
}

// in this page:
async function loadLive(ticker){
  const q = await (await fetch(`/quote?t=${ticker}`)).json();
  DATA[ticker].price     = q.c;            // current
  DATA[ticker].change    = q.c - q.pc;     // vs prev close
  DATA[ticker].changePct = ((q.c - q.pc)/q.pc*100);
  render(ticker);
}

Open interest / gamma walls (the NVDA layer) aren’t in most free feeds — those come from an options-data provider or by parsing your IBKR chain export. Until wired, the other tickers show that layer as an empty state.