A user equipment (UE) is configured to establish network connections for long-term evolution (LTE) and new radio (NR) radio access technologies (RATs) in non-standalone (NSA) E-UTRA-NR dual connectivity (ENDC) operation. The UE includes a multi-antenna array for data and signaling transmissions and receptions over the LTE and NR connections. The UE determines a most efficient antenna of the multi-antenna array for an operating frequency band of the LTE and NR connections, wherein the most efficient antenna is determined based on at least one performance factor for the UE when using the antenna compared to other antennas of the multi-antenna array, evaluates one or more factors for determining whether the LTE RAT or the NR RAT is to use the most efficient antenna and transmits uplink data on the most efficient antenna via either the LTE RAT or the NR RAT based on the evaluated factors.