@MintE the first mentioned tutorial can be found as a highlight on the Instagram account metamui. It's the last highlight, the title is rainbow bracelet and the image is a screenshot of this pattern.
@MintE the advice with the flat alpha technique was a reply to what emily1008 said about her bracelet being puffy but I don't think the flat alpha technique is useful in this bracelet because you can only do it for half of the colour switches in it 🙂
@MintE the most helpful video for a shaped alpha is probably the video by Alex's Innovations on the shaped evil eye bracelet. MashaKnots has a video on a striped bracelet similar to this one but it isn't shaped. 🙂