OK, so when I tested in Postman on the endpoint without the CDN (https://cycleboards.prismic.io/api/v2) I received the time your described (700ms):
But when I tested on the CDN endpoint (https://cycleboards.cdn.prismic.io/api/v2) I received a much lower time of 39ms:
So this makes me think that you still aren't querying the CDN endpoint in your project. Can you check again?