Your zip likely contained a folder of files instead of the files.
Your second screenshot: What you uploaded didn’t include a panel.html file.
Your third screeenshot: you didn’t generate a panel.html file
Your last screenshot: You can’t use “routing” with a single entry point like this in a Twitch Extension. Since the server didn’t route to your entry point, it routed to panel.html which doesn’t exist.
Twitch’s Extension CDN is “dumb” it expects HTML, and you’ve tried to use “intelligence”
For React specific help you might want to pop over to the Developer Discord and post in the Extnesion help (or JS help) channels TwitchDev