We thought it would break and change more easily, but from the first day, the plastic detached from the metal part because the magnet held it tightly. I thought I found a solution with the micro USB cables, but no...

I have been using such magnetic cables for many years, which, in order to support fast charging and data transfer, cost over €16 from China.
This particular one is not only much cheaper, but also much better than those: It has a wider magnet, which may be slightly stronger, and it offers the ability to connect it from both sides. A great advantage, for two reasons. And because you don't have to search for the right side to connect it and because the very strong LED light on the connector is annoying when you look at your phone in the dark.