Hello @rhoc,
Could you please let me know which operator you are using and in which country you are located?
The RUT271 is a 5G RedCap router that supports only standalone (SA) 5G architecture. If your carrier’s 5G network is Non-Standalone (NSA), which operates on a legacy 4G LTE core, the device will not be able to connect to 5G, which would explain why it falls back to 4G only.
In this case, I recommend confirming with your operator whether their 5G network in the area is based on SA architecture.
Best regards,