  The SIDDHARTA-2 collaboration at the INFN Laboratories of Frascati (LNF) aims
to perform groundbreaking measurements on kaonic atoms. In parallel and beyond
the ongoing kaonic deuterium, presently running on the DA$\Phi$NE collider at
LNF, we plan to install additional detectors to perform further kaonic atoms'
studies, taking advantage of the unique low energy and low momentum spread
$K^-$ beam delivered by the at-rest decay of the $\phi$ meson. CdZnTe devices
are ideal for detecting transitions toward both the upper and lower levels of
intermediate-mass kaonic atoms, like kaonic carbon and aluminium, which have an
important impact on the strangeness sector of nuclear physics. We present the
results obtained in a set of preliminary tests conducted on DA$\Phi$NE, in view
of measurements foreseen in 2024, with the twofold aim to tune the timing
window required to reject the extremely high electromagnetic background, and to
quantify the readout electronics saturation effect due to the high rate, when
placed close to the Interaction Region (IR). In the first test we used
commercial devices and electronics, while for the second one both were
customized at the IMEM-CNR of Parma and the University of Palermo. The results
confirmed the possibility of finding and matching a proper timing window where
to identify the signal events and proved better performances, in terms of
energy resolution, of the custom system. In both cases, strong saturation
effects were confirmed, accounting for a loss of almost 90\% of the events,
which will be overcome by a dedicated shielding structure foreseen for the
final experimental setup.
