Unfortunately, there are indeed SIM cards that do not work in routers. Wingo also has such offers, an Unlimited Data subscription for mobile phones and tablets, then there is a somewhat expensive subscription, where it is also advertised that it is also for routers. However, it could also be that an Unlimited Mobile Phone subscription will at some point have a download speed limit, while the subscription recommended for routers (because it is more expensive) does not have this download limit. Not everything that is unlimited is really unlimited all the time and for all data volumes.