The Surface Laptop 5 uses an x86-64 processor (Intel), while the Surface Laptop 7 uses a Snapdragon ARM processor. These are fundamentally different processor architectures, and Windows installations are architecture-specific. You cannot directly clone or transfer a Windows installation between them.
So, your technician is correct.Unfortunately, there's no tool that can convert an x86-64 Windows installation to ARM64. You'll need to do a fresh install on the Surface Laptop 7 and migrate your data separately.