Carrier redundancy refers to having more than one carrier at a time as a means of backup connectivity. If one carrier experiences an outage, then the second carrier comes online to pick up the connection.
Network redundancy means having more than one type of connection available at one time. Normally, this means having a ground-up connection such as fiber running alongside a top-down fixed wireless cellular connection like 4G LTE or 5G. The term can also refer to having connections that come from different sides of the building (i.e., north-south connections); if one severs, the other comes online.