<p dir="ltr">Deploying Open Radio Access Network (O-RAN) compliant 5G networks in complex environments demands rigorous validation across diverse configurations and load conditions. We present a hybrid approach that combines real-time stress testing of a private indoor 5G network testbed and its highfidelity digital model using ray-tracing based wireless prediction software. The stress test is conducted using a commercial User Equipment (UE) emulator, over a live physical O-RAN network deployed at the Future Communications Translation Lab (FCTLab) in SIT. The digital model for the simulations replicates the detailed physical 3D environment of the intended coverage regions for the indoor network. The radio propagation tool simulation, based on ray-tracing, captures the radio signal attenuation, reflections, and diffraction effects. Performance metrics such as Synchronization Signal Reference Signal Received Power (SS-RSRP) and throughput predicted by the digital model are validated against empirical measurements collected using mobile network testing tools. This hybrid framework provides realistic insight into the network performance of the O-RAN testbed and facilitates easy and cost-effective experimentation, such as RU placements and latency improvement under scenarios of connectivity with multiple UEs.</p>