Need to unlink my current twitch account and link a new one but it just keeps reconnecting my old one
Try Incognito Mode in Chrome.
Just go to ur profile and it will give u option to link all ur social medias
clearing cache/cookies on the browser may help if you don't wanna go the private tab route
Can't you just go to your account settings in Twitch and unlink the old account. Then go to the SoT page and re-link the new account?