HTML/JS Page on my PC connecting to Twitch to get data for on-screen scroller; Am I going down the right path?

API
2

  1. Just to authenticate yourself to your own clientID with the relevant scopes to get an access token (and refresh token) to use. See Getting OAuth Access Tokens | Twitch Developers

  2. Not that I can think of. Personally I’d have the HTML/JS/backend service on a server rather than locally. as then it can collect offline subscriptions and utilise eventsub over webhooks instead

But otherwise all good so far I think