"Cachy Browser: Browser based on Firefox, with a more secure config and patches from Gentoo + Performance optimizations."
that's from the Cachy website. CachyOS considers themselves a more-hardened derivative of Arch and this is their flagship browser.
I mean Firefox is a porous browser OOTB and things like librewolf, mullvad, waterfox, even arkenfox profiles exist as a reaction to this: all these tighten up the existing Firefox browser. My thoughts are Cachy Browser is just another one of those 'security-minded' firefox variants.
EDIT: quote at the top from https://wiki.cachyos.org/cachyos_basic/why_cachyos/