  We present and benchmark a quantum computing approach to calculate the
two-dimensional coherent spectrum (2DCS) of high-spin models. Our approach is
based on simulating their real-time dynamics in the presence of several
magnetic field pulses, which are spaced in time. We utilize the adaptive
variational quantum dynamics simulation (AVQDS) algorithm for the study due to
its compact circuits, which enables simulations over sufficiently long times to
achieve the required resolution in frequency space. Specifically, we consider
an antiferromagnetic quantum spin model that incorporates Dzyaloshinskii-Moriya
interactions and single-ion anisotropy. The obtained 2DCS spectra exhibit
distinct peaks at multiples of the magnon frequency, arising from transitions
between different eigenstates of the unperturbed Hamiltonian. By comparing the
one-dimensional coherent spectrum with 2DCS, we demonstrate that 2DCS provides
a higher resolution of the energy spectrum. We further investigate how the
quantum resources scale with the magnitude of the spin using two different
binary encodings of the high-spin operators: the standard binary encoding and
the Gray code. At low magnetic fields both encodings require comparable quantum
resources, but at larger field strengths the Gray code is advantageous.
Numerical simulations for spin models with increasing number of sites indicate
a polynomial system-size scaling for quantum resources. Lastly, we compare the
numerical 2DCS with experimental results on a rare-earth orthoferrite system.
The observed strength of the magnonic high-harmonic generation signals in the
2DCS of the quantum high-spin model aligns well with the experimental data,
showing significant improvement over the corresponding mean-field results.
