Buongiorno,
The SIM card is built into the device and I don't think it can be replaced.
The connection for the first year is included in the purchase price, thereafter, via the application, it is possible to renew.
I can't tell you the cost. SUNRISE appears in the application as a telephone operator. You can try asking SUNRISE for the cost of renewal and check whether there is SUNRISE coverage where you will be using the device.
Saluti.

What now Sunrise or Salt?

The SALT SIM card is permanently installed. It cannot be changed. The costs are included for one year. After that, it must be extended. This is not yet possible. The costs are therefore not known.