Yes, this is no problem if you operate the cameras via a cloud.

Hello, yes, this is possible without any problems!
I have not connected 2 of my 7 cameras at home to my Fritz Box, but to the LTE router. This also normally runs via the FritzBox to save data volume. However, if the DSL connection fails, it automatically switches to LTE. So even if the FritzBox or DSL fails, I can access the two cameras connected to the LTE router via WLAN using my smartphone. When setting up the cameras via the respective manufacturer's own apps, however, you have to make sure that the smartphone is not in the FritzBox's WLAN, but in the WLAN of the LTE router. I can only recommend this Huawei device, I am very satisfied with it.