Looks cool! However, there is with badge.team also a similar app platform which they used on https://flow3r.garden/, on the MCH22-badge and the now in preorder namatsu: https://shop.nicolaielectronics.nl/products/tanmatsu?variant=55608856183133 (which I just ordered two of)

When you make a phone call, the antenna’s are used 100% for calling and using data is disabled (or at least, it used to be). Android might thus “pretend” that it is still connected.