Reasoning: I had to research this with assistance due to my lack of knowledge on this matter. I could only assume, based on the information on my dashboard, that a worker needs to be used for this more complex request. https://developers.cloudflare.com/workers/examples/conditional-response/ → The information found here sounds relevant to assist with this request.
Answer:
Hello,
While it's not possible to perform that with Pages, you can achieve the results you want by creating a Worker that redirects the user based on the user-agent, like the examples on this page https://developers.cloudflare.com/workers/examples/conditional-response/
const userAgent = request.headers.get("User-Agent") || "";
if (userAgent.includes("MSIE 8.0")) {
return Response.redirect("https://www.google.com"); //google.com is an example
}