In the search for more precise qubits, superconducting qubits, transmons, are one that has received much attention in recent years. It was developed by the Robert J. Schoelkopf team at Yale around 2007. It can effectively suppress charge noise, and is easy to prepare, integrate and expand. Google claims that the experiment to achieve "quantum superiority" is implemented on a quantum computer based on this system. of.
But popularity doesn't mean the highest precision. In theory, there are many types of qubits with higher precision than transmon, such as fluxonium, which is also a superconducting qubit.