The CA Matrix is dependent on the RF devices, and how they are configured.
4G+ is NOT dependant on Carrier Aggregation (CA), so your problem of no 4G+ is not related to the CA Matrix.
The prime determinant of 4G+ is the downlink quality (SINR). It can also be blocked by an operator for certain service classes of SIM, i.e. prepaid or low-cost plans - not that this appears to be the situation in your case, as 4G+ is working with 700 and 2600 CA, if I understand your situation correctly.
Is your friend with OP5 using the same carrier?
From what I can see the Operator has LTE700, 1800 and 2600, but no indication which bands they have available for CA.
CA needs to be configured in the network elements, (MME and eNodeB), as they advise the mobile which bands are available for CA.Then the UE reports what CA combinations it is capable of, and if the SINR is suitable BEFORE the network will decide if there is the requirement for CA to meet the downlink demand, prior to sending the UE a Radio Bearer Reconfiguration message to activate it.
My guess is that the operator has not enabled LTE 1800 & 2600 CA, due to capacity limitations or some other technical reason.