I can establish a connection on B1, B5, B28 and B40 LTE bands. However even with all bands enabled, the modem will never enters carrier aggregation. The carrier has several CA options available.
The AT command AT+QCAINFO returns "Error"
I have been in contact with Quectel and they advised to upgrade the modem firmware and have provided EC25EUGAR06A06M4G_01.005.01.005 to install.
However I'm not sure how to apply this firmware update with the modem installed inside the Teltonika router. The update contains multiple files.