I have Salt and since the update to 6.83 I have always had problems. Very slow and today nothing worked at all.
Sim card in the iPad worked. Then I saw that there is firmware version 7.01 for the Fritz Box. I installed 7.01 manually and the internet connection was immediately available. Now everything seems to work again without any problems. :-)
Yes, the Fritzbox runs with Swisscom without a problem! Swiscom is not in the selection of providers. After the setting was entered manually, it works great.