  The eROSITA Final Equatorial Depth Survey (eFEDS), with a sky area of 140
square degrees with depth equivalent to the equatorial patch of the final
eROSITA all-sky survey, represents the largest continuous non-full-sky X-ray
fields to-date, making it the premier data set for measuring the angular power
spectrum. In this work, we measure the X-ray angular power spectrum of galaxy
clusters and groups in the eFEDS field. We show that the measured power
spectrum is consistent with past observations, including the ROSAT All Sky
Survey, and the Chandra COSMOS and Bootes fields. The predictions of cluster
gas halo model that is calibrated from Chandra observations is also consistent
with the eFEDS power spectrum. While the eFEDS does not have large enough sky
coverage to provide meaningful cosmological constraints, we predict that the
X-ray power spectrum from the cycle 4 of the eROSITA All-Sky Survey (eRASS4)
will provide constraints on $\Omega_M$ and $\sigma_8$ at the 10% level.

Cosmology and Nongalactic Astrophysics