The device supports, among others, the 5G bands 1,3,7,28,78 (https://www.gsmarena.com/oneplus_8t... under NETWORK) and thus also the Swisscom bands (n1, n78 https://en.wikipedia.org/wiki...). Even if 5G were to be added in the future to the bands where 3G and 4G currently run, the device would be equipped for this.